Sir Leopold (DQ8) vs. Jowy Atreides(S2)
I dunno if I'm willing to hype double criticals for Sir Leopold which gives him absurd damage, but I think even a crit + regular attack does the job here? Jowy only has .95 PCHP. DQ8 bosses are tanky enough not to get OHKO'd.
Nailah (FE10) vs. Rayquaza(PKMN)
Heavy:
Alexia Lynn Elesius (WAXF) vs. Eirika (FE8)
Doubled and dies horribly.
Kanji (P4) vs. Edgar (FF6)
I didn't actually get Fast Heal in P4G, but... documentation on how exactly it works is sketchy. Does it halve status ailment time? Reduce it to one turn? Who knows. FF6 statuses don't really have durations, but even if we say that Fast Heal cures Air Anchor fast enough to not die, it seems like Edgar can just spam Noiseblaster every single turn and get at least one confused action off. FF6 enemies have their own wacky confuse script from Relm's command so I dunno if P4G confused Kanji can even break his own regen, but whatever, assuming there's some self-destructive HP cost moves in there.
Clarissa Arwin (WAXF) vs. Auron (FFX)
Auron gets very, very few turns due to the turnsplit and Rob Turn. But it just... doesn't matter, because Magic Break doesn't wear off, and Clarissa's backup damage is so heinously bad after spending her HP on Sacrifice. Given that Auron's weapon powers up over time, she actually probably doesn't even want to use Sacrifice ASAP, but rather save it for a finisher (even with low HP), which will at last make Auron's damage similarly bad... until he gets his second turn and Power Breaks her, sending her damage back into the gutter. This is probably one where you'd want to roll it out given that Auron wants to get the 2nd turn ASAP to greatly slow Clarissa's clock.
Middle:
Byleth (FE3H) vs. Sylvain (FE3H)
Close match. With standard DL scaling, Byleth's Renewal is definitely an issue... Silver Lance SS is 0.535 PCHP, Iron Lance SS is 0.425 PCHP, Byleth has 1.11 PDur meaning they regen 0.22 PDur equivalent. Byleth can gamble on a little Crest of Flames healing, Sylvain on Gautier procs for a little more damage. Byleth needs 6 smacks with Sword of the Creator to win. Sylvain wins in three turns off 3x Silver Lance SS for sure, or probably off 2x SL SS & 1x Iron Lance SS.
So assuming no procs and no evasion, Sylvain gets wrecked because 2x Swift Strikes don't kill but Byleth but SotC counters + regular attacks 8 times in the first two rounds. So yeah, Sylvain needs to heft an Iron Lance at least once and just hope for some Gautier procs in there, which would push Byleth down to 6 smacks and at least allow evading one of those hits to win. Of course, even the very scrubby Crest of Flames healing might be enough if Byleth gets 1 proc there, given that Sylvain is already gambling on at least 1 Gautier proc if he goes for the Iron Lance strat.
I dunno. Think this is looking Byleth-favored, 99 Hit on the Creator Sword is still good and 79 Hit is still acceptable with the two random number system. Byleth also has 19 Crit vs. Sylvain's average Luck.
Note that if you throw out DL scaling for fun, Sylvain OHKO's Byleth and Byleth doesn't OHKO Sylvain (unless you spot them a free Death Blow or the like), and Sylvain has higher range, so he wins pretty cleanly under those assumptions, at least!
Florina (FE7) vs. Blanca (SH2)
Nephenee (FE10) vs. Anastasia(SH2)
Light:
Edward (FF4) vs. Karn(BoF1)
Peppor (CC) vs. Linhardt(FE3H)
Chrono Cross boss speed plot! My recollection is that the wacky way CC bosses got turns made them mostly "slow", and Peppor really needs to be seen as at least average, since the way you kill Linhardt is by doubling him. Which is not hard, especially when he's using Nos strats, but not inclined to kneejerk for the CC boss.
Jelanda (VP1) vs. Poshul(CC)
Boco (FFT) vs. Selphie(FF8)
Boco's terrible damage lets Selphie set up for limit nonsense.