Godlike
Melfice (Grandia II) vs Yuri Hyuga (Shadow Hearts Series): I'd think.
Chris Lightfellow (Suikoden III) vs Velna (Legaia 2: Duel Saga): Physical immunity.
Luther Lansfeld (Star Ocean: Till the End of Time) vs Dragon Emperor (Seiken Densetsu 3): The SD3 final bosses had solid damage and ridiculous HP, and Dragon Emperor has a whole host of nasty status attacks and stat downs on top of that. He's really good.
Heavy
Cecil Harvey (Final Fantasy IV) vs Ephraim (Fire Emblem: Sacred Stones): Does Reginleif hit weakness? Does Ephraim double? Should Cecil even bother showing up for this match? The world may never know.
Nel Zephyr (Star Ocean: Till the End of Time) vs Oerba dia Vanille (Final Fantasy XIII): Pain's probably considerably more accurate than SO3 freeze.
Oerba yun Fang (Final Fantasy XIII) vs Solo (Dragon Quest IV): Notably more cleancut than the above, Fang goes first and has Improved Debilitation so Fog spam is very very fatal.
Middle
Lute (SaGa Frontier) vs Melody Vilente (Wild ARMs 3): Lute should 3HKO (has a very low 2HKO normally, but barrier)... but he's slower (slightly below average, Melody is average) and has no immunity to poison, so he eats three Eliminate Scanners and two shots of poison. That's fatal unless you see ES doing less than 20% per shot. lol Lute, I definitely respect him more as a Middle but he gets spoiled here and my sympathy is zero.
Silmeria (Valkyrie Profile 2: Silmeria) vs Meganium (Pokémon): Crits cut through pokemon buffs, so this seems hopeless for Meganium. Snowfire's argument is interesting but I'm pretty sure it takes like 3 fights to pick up Toughness, I certainly did it almost instantly for Hrist/Lenneth/Brahms who I did use.
Garr (Breath of Fire III) vs Paws (Cthulhu Saves the World): Garr sucks.
Light
Garcia (Fire Emblem: The Sacred Stones) vs Mullen (Grandia): Mullen always loses.
Rafa Galthana (Final Fantasy Tactics) vs Palmer (Final Fantasy VII): White Robe probably lets her take the slugfest, yeah.
Sazh Katzroy (Final Fantasy XIII) vs Lucius (Fire Emblem: Blazing Sword): Assuming Sazh can 2HKO Lucius, then he can at worst Haste/Shell to lap immediately and reduce Lucius damage to a 4HKO, and triggers only one counter and sees only two Lucius turns. I guess there's a chance he misses it but eh it really doesn't take much to 2HKO Lucius.
Piccolo (Suikoden III) vs Tim Rhymeless (Wild ARMs 2): Yep.