Godlike
Ted (Suikoden IV) vs X (Mega Man X: Command Mission): Yeah, Elfboy summed it up. Ted goes first (which can be debated since X is fast! But Ted's probably faster anyway), Kills X -> X Heart activates. X goes, transforms, attacks Ted for some damage, next turn, X unleashes his Command Trigger and butchers Ted. This might not kill a normal enemy, but...Ted's physical durability is not what we call high.
Terra Branford (Final Fantasy VI) vs Arceus (Pokémon): Yeah, Break wins it. She can tank two Judgments since its Magical, which means the second one gets halved, and she already had good magic defense to start with.
Heavy
Freyjadour Falenas (Suikoden V) vs Masaru (Live a Live): I'm totally kneejerking this one.
Hollander (Crisis Core: Final Fantasy VII) vs Elincia (Fire Emblem: Radiant Dawn): Hollander has the same exact issues in Heavy Hojo does, which is to say, he doesn't really win...ever...
Ho-oh (Pokémon) vs Auron (Final Fantasy X): Immunes Fire, that kind of screws Ho-Oh over right there. Even playing defensively, Auron will eventually get his Overdrive up, and use Shooting Star. He doesn't even need Zombie Attack to win this!
Middle
Thief (Final Fantasy X-2) vs Cinnamon (Mega Man X: Command Mission): I...think? Wanna say that even if Cinnamon immunes Borrowed time, Thief has the speed and damage edge? Eh, not a match I'm going to think hard about.
Frog (Chrono Trigger) vs Kaeli (Final Fantasy Mystic Quest): Kaeli has more healing than Frog, and if you allow it, she still has Life. Also, she can cast Heal to eventually get Break to kick in and kill Frog THAT way (CT lacks a Stone status, therefor, Vigil Hats do nothing to it.)
Light
Mel (Suikoden III) vs Magikarp (Pokémon): Light vs. Puny.
Sothe (Fire Emblem: Radiant Dawn) vs Reis Dular (Final Fantasy Tactics): I'm kneejerking that Sothe's counters give him an edge, and the fact that getting Bane + Follow Up to kick in before he dies isn't totally unreasonable. Seems like randomness odds are in his favor, I guess?