Snow: The figures I used were the average with Souji and without Rise, since that's, y'know, normal and not weird OK interps and stuff. That said, Silence is a thing. Yukiko can have evasion-whoring, though, and I think some silence resistance? No idea which happens first between her getting a crit and silence, though, and too lazy to math out anything since we don't have crit rates.
There is nothing wrong with my interpretations!
Godlike
Ashera (Fire Emblem: Radiant Dawn) vs Mewtwo (Pokémon Series) - Ashera. Mewtwo is too light-weight here.
Charlton Blunt (Wild ARMs XF) vs Terra Branford (Final Fantasy VI) - Terra. Just far, far more maneuverable here.
Cidolfas Orlandu (Final Fantasy Tactics) vs Cid Raines (Final Fantasy XIII) - Cid. Not even close. Just hard to knock out.
Mei-ling (SaGa Frontier) vs Apocrypha (Radiant Historia) - Apocrypha. Much, much harder to knock out of the ring.
Heavy
Galcian (Skies of Arcadia) vs Wakka (Final Fantasy X) - Galcian. As long as he gets close, he can knock Wakka out easily. Wakka looks heavy-weight, but he's really light. Galcian is really, really heavy (oddly), so he can take a couple balls to the face (much like Jo'ou does on a daily basis)
Legretta (Tales of the Abyss) vs Nel Zelpher (Star Ocean: Till the End of Time) - Legretta. Unlike the above match, this can be a pure range fight here. Legretta wins that handily. Close-range, Nel's got an advantage, but again, she's lighter, so a couple good hits will knock her out of the ring.
Chie Satonaka (Persona 4) vs Rune Walsh (Phantasy Star IV: End of the Millenium) - Chie. Again, Rune's too telegraphed. Chie can dodge anything and then GALACTIC PUNT him out.
Cthulhu (Cthulhu Saves the World) vs Elincia (Fire Emblem Series) - Cthulhu. Seriously, come on - Insanity makes it so Elincia cannot use anything effectively, and SHE CAN'T KILL. It's her main thing - she's great for weakening things with all her special moves, but she HAS to be switched out for someone else. It's a problem with the game here, she's awesome, but the nature of this tournament weakens her so much.
Middle
Dekar (Lufia II: Rise of the Sinistrals) vs Ashton Anchors (Star Ocean: The Second Story) - Ashton. The speed and average weight class is enough.
Hope Estheim (Final Fantasy XIII) vs Nina (Breath of Fire: Dragon Quarter) - Nina. Flying > most.
Yukiko Amagi (Persona 4) vs Syphide (Valkyrie Profile: Silmeria) - Yukiko. Range damage FTW.
Sara (Breath of Fire) vs Warlock (Suikoden IV) - Warlock. Sara is too damn big to be effective here.
Light
Sazh Katzroy (Final Fantasy XIII) vs Kahn (Breath of Fire IV) - Kahn. Speed > most here.
Piccolo (Suikoden III) vs Mia Ausa (Lunar: Silver Star Story Complete) - Probably the closest match here. Both are really light, both are ranged attackers...going with Mia, here. Cryo Shield, well-timed, can reflect things, so...it might help tip things?
Locke Cole (Final Fantasy VI) vs Nina Wyndia (Breath of Fire III) - Nina. Flying helps her avoid most things here.
Elena (Final Fantasy VII) vs Tricia (Soul Nomad & The World Eaters) - Tricia. Better range here.