Godlike:
Shania(SH:FtNW) vs. Worker 8 (FFT): Don't think W8 has anything to put any sort of permanent dent in Shania; she gets way more turns, can heal, and has ranged physicals via La Sirene.
Magus (CT) vs. Citan Uzuki (XG): Don't think Magus has anything to put any sort of permanent dent in Citan; he gets way more turns, can heal, and has haste.
Edelgard von Hresvelg (FE3H) vs. Zio (PSIV): Edelgard could do this with (edit:) 2 shots of Raging Storm, but I'm not inclined to give her that. Certainly worth considering, but eh.
Terra Branford (FF6) vs. Mewtwo (PKMN): I think Terra needs her super-overlevelled spells for this one (Break or Ultima); with her Firaga/Cura/Drain set she's very vulnerable to having her damage shut down with Amnesia.
Heavy:
KOS-MOS (XS) vs. Clarissa Arwin (WA:XF): Rob Turn + Sacrifice x2 does its thing. KOS-MOS evade... isn't good enough to stop that, I don't think. You need at least 19% (assuming neutral Rob Turn hit rate).
Lyndis (FE7) vs. Rufus (VP2): Goes first and 2HKOs.
Maya Schrodinger (WA3) vs. Geno (SMRPG): I think the worst-case scenario for Geno is that he misses the 2HKO after boost, but even then he can boost, chip for the amount needed (his various geno spells charged to various degrees give him lots of choice), and 3HKO while only giving Maya one super-high-damage turn, so thanks to boost he can survive one Calamity Jane and two gatling guns, I think.
Lady Elmina Harken (WA:ACF) vs. Ernst (S5): Ernst gets one-shot as soon as Harken is below half HP, and he does less than 50% of her HP, if not by much (he has 51% damage with his best, Harken has 106% mdur). So there's no reasonable way for him to win.
Middle:
Anastasia Romanov (SH2) vs. Karsh (CC): Karsh has no statusblockers, so Ana should land either petrify or paralysis turn 1 and that's that.
Jessica de Alkirk (L:SSSC) vs. Clive Winslett (WA3): OHKOs with Gatling before Jessica can kill. edit: turn 2 silence should stop Clive's threat and she has time to put him away thanks to his bad speed.
Light:
Marianne (FE3H) vs. Marcus (FE6): Marcus's low damage does not let him get past Renewal + Nosferatu.
Squire (FFT) vs. Mustadio (FFT): Not terribly inclined to consider kiting arguments against someone with 5 FFT move. Heck, Squire could equip a crossbow to negate any possible kiting arguments and probably still outslugs.
Hubert (FE3H) vs. Peco (BoF3): Hm, Peco has 1.25 mdur, and regens 5%. Hubert can do 22% with Banshee which prevents Peco from using his best damage, or 31.4% with Frozen Lance. Latter kills on turn 4 and overcomes Peco's healing. Peco trying to kill with damage seems like it won't work, he 5HKOs. Peco... may want to use Sleep Breath? Sleep duration seems really important and the stat topic doesn't say. But say, turn 2 sleep will let him do some damage with breaths (if those don't break sleep?), or get in some free healing... ehh, really not clear that this will let him win, though it's possible it might if the duration is good.
Queen (S3) vs. Nina (S2): Open and shut, Queen is better at pretty much every physical stat. (Dhyer's stat topic mentions Nina with a Fire Rune, but if you give her that she's clearly not Light.)