Godlike
Chris Lightfellow (Suikoden III) vs Lucia (Suikoden Series): Not really buying Chris OHKOing. So... think Chris is just screwed? She isn't surviving five Lucia attacks short of Silent Lake, SL doesn't let her outslug I don't think.
Velius (Final Fantasy Tactics) vs Belial (Wild ARMs 4): Mm, I think I do see summons going throgh the barrier. Unfortunately I don't think this remotely matters, Belial certainly isn't failing to 3HKO and should interrupt Cyclops, and isn't OHKOed by a Velius physical. She may also just 2HKO.
Ryu (Breath of Fire III) vs Citan Uzuki (Xenogears): Sorry Doc.
Heavy
Nina (Breath of Fire) vs Sharon (Legaia 2: Duel Saga): Idle always debuffs accuracy, but the MA is pretty unavoidable, and status could tilt things Sharon's way too.
Ike (Fire Emblem Series) vs Tiamat (Final Fantasy): Hm, I forgot Ike doubled average in FE9, if barely. Yeah that takes it. More inclined to vote on FE9 since the laguz do less to muck with the averages and give me headaches. If Ike didn't double, I'd probably see Tiamat winning this, AETHER not kicking in fast enough against a 3HKO even if you take the numbers literally.
Keith Valentine (Shadow Hearts) vs Maria Traydor (Star Ocean: Till the End of Time): Faster, yeah.
Strago Magus (Final Fantasy VI) vs Auron (Final Fantasy X): Take a breath mint, Strago.
Middle
Pent (Fire Emblem: The Blazing Sword) vs Jessica Philomele (Mana Khemia: Alchemists of Al Revis): Thundering Hammer is probably turn 2, but does trigger counters, and Pent isn't failing to 3HKO. So... healing? Yeah that works. It's full, so buys her time, Pent can only win with a crit. Sky Present's also a reasonably safe way to win.
Kellam (Fire Emblem: Awakening) vs Yulie Ahtreide (Wild ARMs 4): Protected Yulie actually has nearly average Def, the PDur woes are mostly from her HP. And of course I convert everything to division anyway. So... I think this is right? But could very readily be argued. EDIT: Seems like it depends on exactly where the FE13 kill point is.
Bowman Jean (Star Ocean: The Second Story) vs Bob (Suikoden II): Sure whatever, too lazy to look up Bob.
Melbu Frahma (Legend of Dragoon) vs Mog (Final Fantasy VI): I think Melbu has... a 4HKO in his final form, 5HKO in form 2, against Mog. It's a bit better if you respect Melbu's damage as much as the stat topic, but I really undersells/ignores the HP boosting you have at that point, I feel. Now, Wind Song will heal him 3/8 of the time, and does like 11HKO damage on average. It's non-ITD magic, though, so it runs up against Melbu's 5+ PC mdur, and it like 15HKOs each form. If Mog ever fails to heal 3 times in a row against Melbu form 4, he loses, and that has a 24% chance per 3-turn interval. Plus the chance he dies to any of the other forms. It's gonna happen, guys.
Light
Sanaki (Fire Emblem: Radiant Dawn) vs Banon (Final Fantasy VI): I'm kinda confused by the discussion here. Sanaki 2HKOs, she has a borderline 2HKO to average using the higher listed average and Banon is well below. She counters so Banon's safe openings to attack = virtually never. She also doubleturns Banon eventually. Next.
Katarina (Suikoden IV) vs Selphie Tilmitt (Final Fantasy VIII): Lotsa damage control.
Black Wizard (Final Fantasy) vs White Mage (Bravely Default): WM's huge problem is running out of resources, BM's bad mdur makes that far less of an issue than normal, and her great Mind/MDef makes already crappy BM status even worse.