Norah (Child of Light) vs Rhapthorne (Dragon Quest VIII)
Hmm. No Lightning for Rhappy. Assuming tentacles hype is go in Godlike, and assuming Rhappy can't do the same move more than once... I'm not sure Kaboom! + Exhales Cold Breath will clear the tentacles, but Cold Breath + Anger of the Gods should get at least 1 usually and horribly damage the other. So only 1 Tentacle ever gets a turn, say. Nox should do the 2 PCHP or so required with 1x Sea Serpent's Kiss, 1 Maw of the Deep, and the 1 Tidal Wave that resolves, which will take 3 slow turns to do. Rhapthorne's damage improves a bit as the tentacles fall and Anger of the Gods starts focusing. So... 9x hits from Anger of the Gods ( 2.25) + 3x Exhales Cold Breath = ~3 PCHP or so, yeah, Nox is quite dead. You need to hold Call Team harshly against Rhappy or use the higher level boss numbers I guess for her to turn it around.
Selvaria (Valkyria Chronicles) vs Citan Uzuki (Xenogears)
Elf said that Hyper Deathblows don't have perfect accuracy. Are there any non-Id enemies who dodge them? I would really take any ol' excuse to antivote Selvaria's evade trick.
EDIT: looks like Doc is out of luck. Sadness.
Heavy
Ryogo Kusama (Front Mission 3) vs Margulis (Xenosaga)
Dang, totally time to look up Margulis's XS3 mech form, except that XS3 mech combat is super lame, so never mind.
Anyway, FM3 characters have Fire Emblem-esque counterattacks (except limited by AP), which matches up well against XS2 Margulis's tanky-but-low-damage style. Burst combos also interfere with some sort of a Shadow / healing / stalling game. While I'm skeptical of hyping Ryogo's damage quite as much as the stat topic does, this is still probably his fight, Margulis wants to stall and build combo meter and I don't think he can.
Ryuji Sakamoto (Persona 5) vs Clarissa Arwin (Wild ARMs XF)
Uh... Ryuji is really tanky at 148% durability and 1.35 raw PCHP. That's gonna require, like, 2x Sacrifices & a Howling Shot, or 3x Sacrifices to take down. And an extra poke if Confidant L8 Endure auto-life is hyped up. OTOH, Ryuji's shock gun can miss its proc, just as Rob Turn can miss, and if he's already low on HP he might not be able to use his best damage. Fun with calculating probabilities. Kneejerk is that while Ryuji "spoils" Clarissa with the HP, she wins anyway, 'cuz she's really more a Godlike than a Heavy.
Anyway, did some math, and think Clarissa wins 75% of the time if she only needs 3 turns in a row (no hype for auto-life) and Ryuji wins 76% of the time if he gets a turn and otherwise everything gets reset to turn 1. If Clarissa needs 4 turns in a row (ignoring that she wants to do the finishing blow on a stolen Ryuji turn), she wins about 62% of the time.
Middle
Katsuya Suou (Persona 2: Eternal Punishment) vs Blanca (Shadow Hearts: Covenant)
Huh. Triple Down seems to be .51 PCHP damage, Blanca has... 1.03 PCHP in Dhyer's stat topic, aka barely avoids the 2HKO. So Blanca doesn't run out of MP.
Haru Okumura (Persona 5) va Gen (SaGa Frontier)
No Saga Frontier, but looks like Tetrakarn walls? (EDIT: Er, ignore me. Right, right, use crappy attacks into Tetrakarn 'cuz Gen isn't an idiot P5 enemy.)
Light
Leon (Fire Emblem Echoes: Shadows of Valentia) vs Squire (Final Fantasy Tactics)
Squire is doubling here, but hey, range 1 counterattacks to the rescue?! Anyway, hmm, Squire wants to deal ~410 FFT damage or so, so Power Sleeve setup it is which will kill in 4 hits. Can Leon 3HKO back? Hahaha no, 2x counters + even a Heavy Draw = 35 FE15 damage don't do it even if he equips a Steel Bow and never misses. This is a sorry show, Leon.
Orochi (Fire Emblem Fates) vs Janus Cascade (Wild ARMs 3)
Assuming this is fish-Janus, he seems to have completely horrible damage even when he's doubling, which barely matters 'cuz he's eating murderous counterattacks.
Donnalto Presance (Tactics Ogre: Let Us Cling Together) vs Rufus Shinra (Final Fantasy VII)
Shotgun'd. Donnalto's healing is okay in-game but hilariously bad in the DL.
EDIT: I suppose this is closer than I thought, checking the math, but Donnalto still gives Rufus a lot of time here with his 38HKO - since Donnalto is only barely holding on, inclined to apply similar logic to Seneca vs. Freelancer last week and assume Rufus gets 3 crits in a row or something. Although I guess Donnalto could reserve TP to be able to spam Mother's Blessing in response to such good luck... bah, fine. Shame, Rufus, I thought you had this one.