Heavy:
Daos (Lufia 2) vs Frejyadour (S5)
Luminary (DQ11) vs Stella (Brig:LoR)
Re Elf's analysis... 2x Ambushes -> DD will kill, but how is that a heal lock? Wouldn't it need to be Ambush->DD that kills? If Stella needs 2 Ambushes, Luminary will just do something else after the first one (damage or Sword Stance) and then full-heal after the second one.
Anyway, Faint is kinda similar to Turn Skip which Luminary can reduce or possibly block outright (Catholicon Ring; Not listed in the stat topic, but Archangel's boots should be Act II available and offers 50% Turn Skip protection for an Act II interp), and Ambush is only listed as a 30% chance of Faint anyway. I think Stella needs Faint hype to win here though due to the above reason. Secondly, I'm a bit skeptical of letting Brig2 characters "double" (threat range is fine for initiative, but not necessarily doubling... i.e. if changed into ATB turns, it'd be like having a turn at 80, 180, 280, 380... rather than 80, 160, 240, 320...). But even if you do let Brig2 characters double, Luminary may be fine. At the levels Elf listed in the topic, Stella only gets 6x Ambushes before she won't have enough MP left for DD, meaning she needs to get a double fairly quickly. Worse, Luminary has a 10% block rate on his shield, and a successful block will let him do some annoying stuff- Sword Stance if nothing else to harvest more blocks/parries and make Stella run out of MP while he outlasts with healing. If you want to get *really* fancy, he can cast Kaclang for invincibility as a last resort upon expecting an incoming double... it can be an unreliable strategy in-game with random initiative, but even with some random chance to backfire, it is a genuine way to survive charged up horrible turns of doom in-game, so it's not a totally troll strategy.
Middle:
Squall (FF8) vs Setsuna (Setsuna)
This one is interesting. Sure, 3x Luminaires kill Squall before he doubles, but 2x Luminaires deal ~0.8 PCHP damage (Setsuna's damage is average) which knocks Squall into Limit range. Assuming you're generous about letting FF8 characters find limits quickly (I am), that is extremely bad, although Squall won't technically have that much time on his third turn to "find" the limit with repeated turn cancelling. Still, this isn't a totally closed case... Setsuna can go Luminaire-> healing and hope to kill with a massive Holy Light. Problem is she's slow (listed as 83% speed) so I don't think she builds up quite quickly enough, Squall gets a double reasonably quickly. However! Setsuna has one last hope... she can stall with healing. Squall needs to keep attacking in, because if he doesn't, Setsuna will safely chip with weaker damage and evade the limit. But taking damage is what builds Momentum in IAS very reliably, and Momentum is a horrible thing to give Setsuna. Even if she started with 0 Momentum, she'll get a bar, and then cast Luminaire with Momentum and apply Auto-Life to herself. Even after she dies horribly from getting Lionhearted, she'll just wake back up again then KO Squall.
Mario (Mario Rabbids) vs Nergal (FE7)
Light:
Primrose (Octopath) vs Dorothea (FETH)
If you let Primrose get powerful physical Allure targets (i.e. the overlevel Assassin in the stat topic), then... she might still lose, but at least it'll be close.
