Godlike
Necrosaro (Dragon Quest IV) vs Zack Fair (Crisis Core: Final Fantasy VII)
Persephone (Wild ARMs 5) vs Terra Branford (Final Fantasy VI) - She immunes Fire. I allow Terra to have Ultima, but I think Persephone's just outspeeding her too much.
Garm (Valkyrie Profile: Covenant of the Plume) vs Xorn (Grandia III)
Emily (Suikoden III) vs Fou-lu (Breath of Fire IV)
Heavy
Kain Highwind (Final Fantasy IV: The After Years) vs Edgar Roni Figaro (Final Fantasy VI) - Air Anchor ruining Kain's big promotion.
Esuna Busy (7th Saga) vs Hildagard Valentine (Shadow Hearts: From the New World)
Sara Valestein (Trails of Cold Steel) vs Mother Brain (Phantasy Star II)
Fencer (Bravely Second: End Layer) vs Merurulince Rede Arls (Atelier Meruru: The Apprentice of Arland) - I'm assuming Meruru is at least getting access to her basic Alchemy items, because without them, there's no way she belongs in Heavy. She has a lot of Full Healing and Buffing options, and is durable enough that Fencer can't ORKO. Fencer can try to blitz on the second turn, but by then Meruru's buffed her durability by half (or more, depending on whether she needed healing too). With buffs in place, Meruru can easily alternate between heals and damage, and only needs 3 turns of Bomb Ice damage to end this. If Fencer opts for the Water-halving headgear (I don't recall if Water counts as Ice-elemental in B2nd), then there *might* be an argument for Fencer outspeeding with some Falcon Stance speed-buffing and getting a doubleturn at some point? Meruru's Items already have decreased wait times on them, so I dunno if it helps.
Of course, if you allow Meruru a full Pepped Up basket so that all of her healing items can auto-proc when she takes damage, then Fencer's only option was to OHKO, and that's just not happening.
Middle
Shante (Arc the Lad II) vs Sylvain Jose Gautier (Fire Emblem: Three Houses) - Can Divide get around his counters somehow?
Ursula (Final Fantasy IV: The After Years) vs Alfyn Greengrass (Octopath Traveler) - leaning this way based on poison hype~
Rabbid Peach (Mario + Rabbids Kingdom Battle) vs Hendrick (Dragon Quest XI: Echoes of an Elusive Age) - I think she has trouble getting enough damage in before Hendrik buffs up to OHKO? There might be some scenario where she can ensure that she always has Shield up before Hendrik gets a turn which could make this match last forever...
Messam Elmdor (Final Fantasy Tactics) vs Bob (Suikoden II)
Light
Chemist (Final Fantasy Tactics) vs Norris (Chrono Cross)
Harley (Final Fantasy IV: The After Years) vs Kongol (Legend of Dragoon) - surely not even Kongol is slow enough that Harley can put together enough offense to take out his durability before he handily whups her.