Godlike
Katrina Liane Elesius (Wild ARMs XF) vs Celes Chere (Final Fantasy VI): This might be an intriguing fight if not for Shrine Maiden Glancer.
Jecht (Final Fantasy X) vs Carbuncle (Final Fantasy V): Carbuncle doesn't actually cut magic by that much... 15% or so compared to Exdeath (who isn't average, but is what I use as my benchmark for damage for simplicity). And Carbuncle's HP... I'd assume a damage average of around 2050, so he's 84% PCHP. Carbuncle is... probably faster, though I'm not sure exactly what speed to take him against. So Jecht needs to avoid 3HKOing the first phase. Jecht Beam does 10.5%, cutting that by 15% means 9%... just misses doing 28% over three hits. Super-close!
Heavy
Garnet til Alexandros (Final Fantasy IX) vs Knight (Bravely Default): Protect then some status, probably.
Ike (Fire Emblem Series) vs Ominas Crowe (Bravely Default): Sleep's nice and all, but isn't really needed when Ominas has a 2HKO with Fire...
Tony Eisler (Mana Khemia: Alchemists of Al-Revis) vs Angelo (Dragon Quest VIII: Journey of the Cursed King): Angelo gets heal-locked by someone with break damage, goood luck with that.
Lucario (Pokémon) vs Artea (Lufia II: Rise of the Sinistrals): 2HKOs first. Lucario does have a pretty mean strategy here with Close Combat + Extremespeed, but that misses the 2HKO on Artea.
Middle
Typhlosion (Pokémon) vs Lich (Final Fantasy): Oh my, 35% average durability against fire magic, Lich?
Juno (Soul Nomad & The World Eaters) vs Hope Estheim (Final Fantasy XIII): Hope under Protect isn't 2HKOed... but Juno can buff to get that back to 2HKO, or turtle with a shot of healing. And her turn 5 limit is a win. EDIT: Hm, actually, it's water, so Hope can survive it with Protect + Barwater. But not if Juno has buffed. I think the fight goes...
Juno: Attack to force Hope to heal
Hope: Haste/Protect (Hope doubles immediately, but won't again before turn 5)
Hope: Heal
Juno: Attack (3HKOs)
Hope: Use some attack sequence, presumably 3HKOing. Alternatively he uses Faith/Barwater.
Juno: Attack
Hope: Must heal or Juno attacks him and he dies
Juno: Bold Move
Hope: Still can't complete the KO
Juno: Attack + special, KOs through Protect+Barwater
Yep.
Barret Wallace (Final Fantasy VII) vs Sain (Fire Emblem: The Blazing Sword): Yeah I doubt Sain is avoiding Hammerblow.
Light
Algus Sadalfas (Final Fantasy Tactics) vs Swordmaster (Bravely Default): Counters get around Auto-Potion! That's something. This is pretty close, but my kneejerk is the stat topic undersells Swordmaster a little... even without Norende there are three katanas better than Masamune and not many PCs would want them...
White Wizard (Final Fantasy) vs Nina Wyndia (Breath of Fire III): Element resistance probably wins this?
Mao (Shadow Hearts: From the New World) vs Emma Hetfield (Wild ARMs Alter Code F): I'll admit I'm mostly voting this way because the idea of Arc-en-Ciel being a turn 1 fatal status move makes me twitch. It's arguably 70% here, but confuse/sleep can wear off randomly making it worse? That works.