Godlike:
Magus (CT) vs. Arceus (PKMN) - Kneejerk. I have to imagine that there's a typing that gives Arc a way to mitigate most of Magus' damage. Maybe something like Rock typing (halves fire/phys)?
Belial (WA4) vs. Edelgard (FE3H) - Unless you let Edie repeatedly activate Raging Storm, I have no idea how she gets through Distortion spamming. If you do, she wins if she gets a turn, but it looks she might have issues doing that too (see Snowfire).
Nailah (FE10) vs. Shania (SH3) - Magic's probably right IF you see Shania going first. The issue is...the argument for Shania going first is pretty weak. She can't start off in a transformed state, meaning her opening speed is below average (98%). Under most common evaluations, Naliah has both a) Better raw Speed (she's either average OR above average in FE stats) and b) Better move speed. And if Naliah goes first, her first hit is going to rip off a chuck of health - possibly a ORKO depending on the average, so she absolutely needs to go first to have an argument.
Heavy:
Maya Schrodinger (WA3) vs. Alexia Lynn Elesius (WAXF) - Huh. Alexia falls into the right side of the damage average (low 2HKO) against someone who has exactly average defenses. And since Maya is only listed as "Average" Speed in the stat topic, that's not fast enough to actually double Alexia. So she goes first, 2x Revolver Sweep and collects victory, completely bypassing Calamity Jane range. Who woulda thunk?
Haishao (XG) vs. Kanji (P4) - LMAO. Even if you don't give Kanji Ziodyne for whatever reason, he likely still outslugs because he immunes Electric Arm counters.
Guv(DQ8) (No Call Team) vs. Clarissa Arwin (WAXF) - Pretty standard Clarissa win, I think? Double Rob Turn into Double Sac means Guv has no way to get a turn to actually heal inbetween. If Rob Turn misses though, she's in deep. Two 75% chances means there is a 43.75% chance for it to not happen, so like Snowfire noted, not reliable in a series of matches, but passable in an individual case.
Ness (EB) vs. Worker 8 (FFT) - EDIT: Confirmed in Chat. Compress doesn't actually inflict ID. So yeah, Ness turtles up and wins a slow fight. W8 can't really break past the stalling without ID - Work might not be physical, but using it drains his HP even faster. Ness is going to cast Shield to soften counters and then just very slowly chip W8 out. His resources are massive if he isn't blowing it on Rocking Omega.
Middle:
Aht (RH) vs. Fafnir (WA3) - So Aht has this move called "Super Heal". Fafnir wins against duelers who can't put out enough damage in time. Healing essentially buys Aht that time. Unless you think she's 2HKO'd (and tbf, her durability in the stat topic is pretty trashy), there's no way she loses this. If you do, this gets more interesting, but Aht's has other advantages going into this (her speed and trap damage for starters) that likely carries
Nephenee (FE10)vs. Aika (SoA) - Uh yeah, this is a case of a Tier 3 Super move coming to the rescue. Neph might even tech to a Killer weapon to put the crit pressure on.
Light:
Edward (FF4) vs. Berserker (FF5) - Oh Super~?
Peppor (CC) vs. Lelei (S5) - So both kind of suck BUT Lelei can get armor that gives her elemental resistances. Without too much digging, I have to imagine that gives her the advantage
Tony (WAXF) vs. Jelanda (VP1) - This is a PUNY tier level slapfight. Going to just copy Random cause I am not thinking about this.