Okay, going to start on this. In-depth analysis, so it'll be slow.
Assumptions: FE6-8 enemy hit taken as 125, FE9 as 140, FE10 as 165. Weapon triangle is taken as the avearge of its effects between games. Weapon triangle does exist. Ike10 and Elincia get their authority boosts; without those they lose a few more matches I think. Will add notes on that later.
Eirika vs. Elincia: Eirika 2HKOs, and doubles. Both are melee, so after their first combat exchange, Elincia is dead. All she can do is pray for Stun... and first turn Stun is yeah no.
Eirika vs. Eliwood: Eirika 3HKOs with the Rapier (30 damage), and doubles. Eliwood 3HKOs back at best, and accuracy/evade concerns favour Eirika even if Eliwood goes for a lance.
Eirika vs. Ephraim: Eirika doubles with the Rapier, doing 27x2 damage, a 3HKO to average and 4HKO to Eph. Eph uses Reginleif for 50 damage, 2HKOing soundly. Which means both two-round each other, but Ephraim's two-rounding always happens first, since Eirika needs a double to finish hers. Eirika evade to the rescue? Hardly. Weapon triangle + Eph's accuracy take 27 points out of her evade, reducing its real value to 19%. Ephraim's is only slightly worse. I'm not going to consider that to tilt this match.
Eirika vs. Hector: Axes do not hit Eirika, that doesn't even warrant examination. With a sword, Hector can... 3HKO while being solidly three-rounded (5HKOed) back (Rapier), since he lacks Armads' defensive boost, and still faces someone who evades over half his attacks.
Eirika vs. Ike9: This one is crazy. Okay. Eirika only doubles if she's not weighed down. This means she's falling back on a Killing Edge. That can't crit. Still her best option. 18x2 = 36 damage = kills Ike in six hits. Ike, meanwhile, 3HKOs back. Doubles offset counters. However, Eirika, when she drops Sieglinde to not be weighed down, has 65% evade. Ike drops this to 63, but it's still crazy. If Ike goes first, he needs to hit three times in six attempts... 40% chance. Now, granted, the times he fails to do this he still gets an average of 1.5 hits, 0.75 of those on average at melee, so he -could- activate Aether to tilt things... but then we consider the possibility that Eirika goes first, which should tilt things back. Eirika does miss Ike about 5% of the time (25% total chance of a miss or so), but this is less significant than Eirika going first, and the match was already swinging by a hair. The tiebreaker to me? I don't respect occult skills activating on the first hit or two, just like I don't respect FE crits doing the same thing. But damn, excellent match.
Eirika vs. Ike10: I may have underrated Ike10's most important advantage, at least in FE vs. FE matches: 14 points above average accuracy. i.e. hey Eirika only dodges a third of the time now, instead of nearly two thirds. Now, granted, she gets a damage by having access to Sieglinde, but she's still only 5HKOing. And Ike can hit her three times out of four when she's weighed down no problem. If she tries to scrounge up those extra points of evade, then she's down to 7HKOing against someone still way more accurate than Ike9. That ain't working.
Eirika vs. Lyn: Eirika 2HKOs Lyn. Lyn does not 2HKO Eirika. Not even with Mani Katti. Nothing else is going to tilt this, but if you need any more evidence, Sieglinde is more accurate than Mani Katti and Silver Sword both by a notable amount, and Sol Katti gets Lyn doubled.
Eirika vs. Micaiah: Thani hurts, but Eirika 2HKOs and doubles. Micaiah may well win if she goes first, but there's a good argument for her going second (Eirika has a horse, Micaiah has mage move) and as always, evade/accuracy concerns are going to favour Eirika too.
Eirika vs. Roy: Roy has 37 points above average accuracy. Yeah. I was stunned too. Anyway, it means Eirika kinda fails at dodging him. She can use Sieglinde and still double, and she 4HKOs since Roy's only as durable as Ike9, not Ike10. But Roy is 3HKOing, range offsets doubles, and Eirika's evade against him with Sieglinde is 6%. Ouch.
Defeating Eirika without good accuracy is a tough prospect.
Elincia vs. Eliwood: Ouch, didn't see this one coming. Anyway, both Eliwood and Elincia 2HKO each other, and lances mean that accuracy/evade concerns are... similar. Now, 2HKO means both want the other to attack first (whoever does so tends to lose). Eliwood however, can attack first with a Javelin, counter with a Javelin, then finish with either Slim Sword (if both Javelins hit) or Durandal (if one hit) for the kill. Odds are only 16% of him missing both Javeilns, and ~15% of missing the killing blow with Durandal (less with Slim) so looks like he wins. Not hyping Stun on one attack, get used to this.
Elincia vs. Ephraim: Good news for Elincia: she narrowly avoids a double! Bad news, Ephraim can pull the same stunt with Javelins Eliwood can. And outright 2HKO with them. And he's way more accurate, and more evasive. Yeah.
Elincia vs. Hector: Okay, finally. Hector can use Armads and still not be doubled (barely), but then he hits less than half the time. He does 2HKO, but Elincia is, by her second attack, going to activate Stun, which is like the damage of a bonus attack, then avoids a counter, then Hector doesn't attack next turn... so it's like three bonus attacks. She'll have five attacks before Hector gets two, and that's almost all the way to killing him. Gets even worse if she gets a Stun chain going. Point is, Hector's not winning. Hand Axe tricks are of no help since they hit approximately never, unlike Javelins. Yay weapon triangle and Hector skill. Honestly, his best bet is to 2HKO with an Iron Sword, which is more accurate... but he's still losing accuracy/evade concerns by a notable amount.
Elincia vs. Ike9: Ike9 doubles, and dodges counters himself. So Elincia attacks once, then Ike attacks four times. He's 2HKOing. Elincia doesn't dodge over half the time. It's not a pretty picture.
Elincia vs. Ike10: This time, Ike doesn't double! On the other hand, 14 above average hit makes Elincia's evade 13%, which I ain't hypin'. So Ike just counters and smashes on his own turn.
Elincia vs. Lyn: Ouch, 2HKOs and doubles with a bow. Elincia's more accurate than bow-Lyn, but Lyn's more evasive, and it roughly cancels. Should be Lyn's match as a result.
Elincia vs. Micaiah: A use for Elincia's Res! (Whereas Micaiah, whose res is o_O, never gets one in this entire set. Lame.) Elincia staves off a 2HKO, so she attacks, gets countered, gets attacked, and kills. Nosferatu doesn't help since that second attack is probably carrying Stun.
Elincia vs. Roy: See Elincia vs. Ike10, only this time, Elincia's evade is down to like, 1% or something.
Kinda disappointing, but Elincia does get spoiled a lot by counters, thinking on it (if she's just getting 2HKOed by people going first, she can use a staff for awesome regen). Not to mention all the silly accurate people.
Eliwood vs. Ephraim: Reginleif 2HKOs, Eliwood doesn't, Eliwood does nothing better than Eph. Yawn.
Eliwood vs. Hector: Godliness. All right. Hector probably doesn't want Armads due to that getting him doubled. He can use Wolf Beil and barely 2HKO, but that means his hit is 22 below average (70% Eli evade). Eliwood meanwhile can Rapier for a 5HKO, and will always hit, so that should win. Alternatively, Hector can go for swords again... hmm. Alternatively, Hector can pick up a Slim Sword and 4HKO with that. This drops Eli's damage slightly, and now he only has 13% evade.
Eliwood vs. Ike9: Well uh Eliwood's 0.4 above average speed means Ike doesn't double! If Eliwood weren't weighed down by Javelins... as is, oh well. His best bet is probably a (no-crit) Killer Lance, which sounds similar to the Eirika situation. WTA gets him to avoiding every other attack, which exactly cancels Ike's attacking from range. Not near good enough.
Eliwood vs. Ike10: As above. Eliwood still gets doubled with a Javelin (Silver Lance is safe if you allow it), and his evade is now worse.
Eliwood vs. Lyn: Eliwood 2HKOs with Durandal (and with... good borderline accuracy to hit twice), Lyn 3HKOs and doubles with Mani Katti, so... hmm. Actually this is familiar, Elincia match redux. Accuracy/evade concerns favouring Lyn, but can Eliwood try his Javelin stunt again? If he does, Lyn double Silver Bows him to avoid WTD, then Durandal for the kill, then Mani Katti to complete the 3HKO. Eliwood's hit rates, again needing only one Javelin: 39%, 17%, 66% = 1/3 chance of getting what he needs. Lyn has hit rates of 85% on the other hand. Good fight, but Lyn evade carries the day.
Eliwood vs. Micaiah: Micaiah mocks Eliwood evade and isn't doubled, while easily 2HKOing with Thani. Eliwood's only hope is to try a Javelin and make it a "who 2HKOs first" match, except then he massively loses acc/evade concerns.
Eliwood vs. Roy: I think Teo McDohl had some quote about this.
Oh well, Eliwood, at least you killed Elincia. And the fights against the fellow FE7 lords were close!
Ephraim vs. Hector: Good stuff. Hector's getting doubled, so he equips Armads, gives up his last shred of evade, and 3HKOs while being a supertank. That plus WTA means he's basically gotten past Eph's evade, though Eph still dodges more than he does. Eph doubles, though, and... kills in either five or six? If six, advantage Hector, if five advantage Eph. Eh. This is, admittedly weirdly close, but Reginleif can be argued to have a defence-piercing property when hitting weakness, so... yeah. Inclined to tiebreak that way at worst.
Ephraim vs. Ike9: WTA means Ike hits less than half the time, which more than offsets counters. And Eph 3HKOs while Ike 4HKOs to boot. Javelin strategies are possible, but not needed.
Ephraim vs. Ike10: Eph's evade is down to 36% or so, and he now misses the 3HKO. This makes things pretty tough, since Ike is now getting 6-7 attacks which is easily enough. Eph can retreat to Javelins (x4) and then finish with Siegmund, leaving Ike with either four or five attacks... which still favours Ike. Before silliness involving Aether.
Ephraim vs. Lyn: Lyn can, to her credit, double with the Mani Katti for damage that... might just 4HKO, even. Too bad Eph 2HKOs and reduces her evade to 13%.
Ephraim vs. Micaiah: Doubles with Siegmund. The end! No, Nosferatu damn well does not let her survive a double, she's borderline OHKOed.
Ephraim vs. Roy: Eph can 3HKO with Siegmund, but Roy has counters on that and he... basically never misses. Damn, Roy's accuracy is Wakka-like. So Javelin x3 -> Siegmund? That actually works decently well, both now 4HKO. But... after WTA, Eph's evade is 6% and Roy's is 25% due to Javelins being unimpressive. Victory to Roy on average.
Ranged swords with high accuracy trumps even Eph, it seems. Damn, I was pulling for him to sweep, even though I didn't really think it would happen. *unwinds time four months, hypes Eph as sweeping the FE lords released in NA games at least!*
Hector vs. Ike9: Well, Ike doubles and counters (Hand Axe isn't happening against a swordsman), so Hector equips Armads and hopes for the best. This isn't... toooo bad a fight, even? Hector is 3HKOing, Ike is... 10HKOing or so? Still, swordsman means Ike probably dodges Hector once in there, and is likely winning even if he doesn't.
Hector vs. Ike10: Well, if Hector's not weighed down here, he won't be doubled. That means no Armads though, so the two are... pretty comparable on durability now, and Ike is still attacking twice as often. With accuracy concerns on his side. Yeah.
Hector vs. Lyn: Mani Katti vs. Armads: Lyn does 54 damage a round, probably five-rounding or so, though crits could be a factor to make it four. Hector 2HKOs, but has troubling hitting. A lot of trouble, less than 25% of the time. That's not going to work. The other option is the SLIM SWORD, but now Lyn kills in three rounds. Hector also kills in three, but he's still missing a third of the time or so. Pretty much Eliwood vs. Hector redux, only this time Eliwood is doubling.
Hector vs. Micaiah: Neither doubles, Micaiah has range and 2HKOs. Only way Hector can match this is with a Hand Axe, but this gives Micaiah a large evade advantage (and both 2HKO each other).
Hector vs. Roy: See Ike10, only with more evade to give Hector even more problems.
Yeah no surprises there. Losing weapon triangle, hit/evade, and AS concerns tends to offset the insane physical durability. Still kinda surprising that the most physically durable lord would get only two wins in eight physical contests.
Ike9 vs. Ike10: Too lazy to calculate if Ike10 actually needs an extra hit to be killed, because it doesn't matter. He definitely has better accuracy, and an 18% melee Aether rate still trumps 0. So at worst the non-concrete favours him, too.
Ike9 vs. Lyn: Lyn dodges every other attack, Ike counters. Offsetting each other! Still, Lyn kills in way more attacks. She'd win easily with 1 more speed (since Silver Bow is >>> Killing Edge for non-AS-lowered Atk); as is, too bad.
Ike9 vs. Micaiah: Doubles whee. And 2HKOs. At isn't 2HKOed. Yeah.
Ike9 vs. Roy: See on site! Basically, Ike9 misses the evasive Roy a bunch, which is way more important than Aether.
Pretty middle of the road. Ranged counters are really cool, as is doubling average. He's not especially good at anything else, but not bad either. Eliwood++ really, really fits.
Ike10 vs. Lyn: See Eirika vs. Ike10, only now Ike10 2HKOs.
Ike10 vs. Micaiah: Doubles. If Micaiah attacks first he counters and wins. If Ike attacks first she uses Nosferatu to survive, then on her own turn kills with Thani (simply because it's more accurate). So the question is, what could cause this NOT to happen? Both have pretty negligible evade against each other (at best, Ike10 has 12.5% evade against the Nos shot). Neither can crit. If Ike is forced to go first, he gets to melee, and has two chances for 18% Aether while Micaiah has one 30% Corona (=30% overall to win, plus some evade). If Micaiah goes first... 30% Corona, but Ike still may hit at least twice in the three tries he gets before Micaiah gets her finishing counter in, so less than 30%. Yeah, on average favours Ike... BARELY. Why is the match between one of the best and one of the worst so close? Wait, Nihil. Forgot that~
Ike10 vs. Roy: Roy still has a bit 20% evade or so, though not what he's used to. Roy doesn't miss. Ike kills in four, Roy kills in five. Roy actually crits (12%, boosted by Ike's Luck to 17 or so), Ike Athers on his own attacks 18%. I... yeah, going to vote Roy. Roy wins... hmm. 60% of the time if he gets the fifth attack in, but only 20% if Ike does. Before crits, which... granted tilt things back his way, but not enough + I don't respect crits much so I won't calculate to be certain. Obviously letting Roy heal would completely let him dominate here.
Really set up to crush other FE characters. Enough speed to not be doubled by those with remotely comparable physical durability, and enough hit to give the dodge whores some problems. Even has Nihil!
Lyn vs. Micaiah: Doubles with a Silver Bow, Micaiah could easily miss the Nosferatu she needs to survive. If it hits, she likely misses her next shot, and the process repeats next round.
Lyn vs. Roy: Too easy.
Lyn's pretty much Eirika minus a few things which add up. The biggest one is damage. Silver Bow is a nice option, though.
Micaiah vs. Roy: Oh hey Roy's Res fucking rules.
Micaiah's neat. I look forward to seeing her in the DL. Didn't get to use her OMGWTFBROKEN magic durability here, but it did exploit her flaws otherwise. Nosferatu is still cool.
Roy... kinda expected him to sweep. He's generally speaking Ike9 with crazy accuracy and good evade, so if Ike9 is Eliwood++, then Roy must be Eliwood++++? Something like that. Definitely the best overall dueller here, since this field didn't let him show off his excellent magical durability, something the other modest physical spoilers like. Really thinking he might be Godlike. Unquestionably is if you let him heal. Roy's our boy, I guess.
Done! Yeah.
Ike10 9-0
Roy 8-1
Ephraim 7-2
Eirika 6-3
Ike9 5-4
Lyn 4-5
Elincia 2-7
Micaiah 2-7
Hector 1-6
Eliwood 1-6
Offhand, Ike10 without his +15 hit/avoid loses to Eirika, Ephraim, Roy, and Micaiah. This drops him to roughly Ike9's level. Which... makes sense!
Elincia without her +15 hit/avoid possibly to Hector? Not sure.