Screw it, this entire post is being editted into an update!
Steiner:
Beat it first attempt without a single hitch. Terra, Lulu and Kuja doing constant 9999s, Tyro's damage sucked and I should have given him Phantasm, Yuna just kept doing green numbers.
The only notable thing is that Kuja did die as a result of Memento Mori late in the fight, but there's no Death condition, and the fight was pretty obviously under control there, so it was an expendable death.
Kuja:
I had 3 successful runs that were Experts, a few failure runs, until I finally champion'd with this set up:
NOTE: The Kuja fight screenshot is taken after the fact, so wrong RW. The Actual RW chosen was Vincent's Chain Shot and yes, that was meaningful. To be fair, I probably could have gotten away with the RW listed.
First to explain the failure set ups:
Originally, I used Seifer w/ Dark Bargain + Saint's Cross. I figure Bloodfest is great for this fight, Dark Bargain + Saint's Cross should allow for big damage, especially with Excalibur boosting Saint's Cross, so that should offset the lack of synergy This set up also had Tyro w/ Dismissal instead of Phantasm, because I forgot he wasn't using a physical waepon, so Tyro's turns were basically worthless damage wise.
No big, I thought; I can redo the fight, give Tyro Phantasm because I don't trust Kuja's resistance (and heck, Steiner no doubt has less, and even with Mage Meta AND Fire Boosting, Tyro's damage was pretty bad), and that should be fine!
...nope, that fails too. I deem Seifer the weak-link because he's stuck at level 65, so instead substitute in Steiner. He can't use Dark Bargain, but he does get Synergy, and can get to level 80 (Seifer's stuck at 65), so I egg him up a bit, Egg him up a bit, and give him Banishing Strike because I figure a 2.4x damage attack (post Excalibur, remember) should help compensate for lack Dark Bargain, and Steiner DOES have a Soul Break for some extra ammo.
That set up also had RW for Fenrir Overdrive (previous two used a defensive one, I think Divine Guardian), which I figured would also alleviate Celes' relative lack of DPS.
...this fails too! Ok, let's try Carbuncle instead since Celes might be a missing link...I learn this leads to Kuja going into Flare Star Happy mode and uh, yeah, not much I can do about that. Won't go into all my failures.
Eventually, I just crack down and make a 2nd Lifesiphon, thinking Auron hurling Banishing Blades at reasonable Intervals might do more than a Saint Cross strategy, and sure enough, that worked! Auron chosen because the two other physical SSBs I have besides Celes are his and Vaan's, and Vaan's is clearly worse in this fight (less damage, attack boost is redundant with shout, and Banishing Blade also has stackable defense lowering, increasing the damage slightly of most of the team.)
Things I take away from this fight:
-Celes really can't do damage without hitting weakness. Tornado Strike with Shout was doing about 8k damage. This really explains why they eventually gave her Knight 5, because even with Indomintable Blade, unless the fight is tightly designed around making Runic good, she really struggles to commit to the fight if they aren't weak to an element. Most physical damage dealers are either SUpport characters who don't need damage, have some major DPS skill like Thief's Revenge or Saint's Cross, or have Lifesiphon, and thus can hurl strong Soul Breaks in between; Celes in her current state can't do any of that. best she has is Flare Strike, which is 1 hit at 3x damage, and is only usable by 2 other characters (Bartz and Squall), so there's really no point in using those orbs (and I think that list gets expanded to Paine and Delita in the future, with Lightning and Cloud getting Spellblade 5 via Record Dive? Still a very small group.)
-The fight really did not live up to the major hype people were going on about. Now granted, I did have Indomintable Blade, but from what I can tell, Magic Lure + Reflect could work reasonably well if I sat down and figured out a set up that'd do that. Now, mastery is hard because of only 2 conditions, but for a fight that was hyped as the "Hardest Ultimate+ fight outside of Caius" it really didn't live up to the hype at all. It's just way too straight forward and simple, and the game even says "LIGHTNING RESISTANCE, NOW!"
-My mastery may have come as the result of VIncent's Chain Shot stacking with everything. This makes me feel dirty inside. Seriously though, chain Shot allowed Tyro with his stick in front row to do over 4k with Magic Breakdown, and pushing PHantasm from just under 5k to just over 6k. I wouldn't be shocked if Tyro being able to DPS on all his Non-SG actions played a role in the actual mastery
-Yes, Ramza was using an instrument and surprisingly his attack stat was decent. Fairy Flute+ w/ Synergy actually was stronger than anything Ramza could use save for the Ultima Sword that Celes is using, and it was Back Row compatible. With Shout, Ramza's damage was passable enough, seeing as he was mostly there for Full Break and Shout, sometimes the occasional "Throw Meteor" when I know Shout wasn't worn off and confident he could get his gauge up before it did.
Anyway, fight's done with, and I have 3 more MSOs!