Blue Mage and Summoner (Final Fantasy V) vs Groudon and Exeggcutor (Pokémon): Yeah, Eruption + Solar Beam kills Summoner and does a bunch of damage to Blue Mage. At this point Blue Mage can... status out one of them, but either can finish the 2HKO next turn. Or use Vampire, but that doesn't KO and then both are around to 2HKO. Or Mighty Guard, but then the combined damage of both kills. Yeah, the opponents just have too much magic damage, too fast.
Lightning Farron and Snow Villiers (Final Fantasy XIII) vs Hiro and Jean (Lunar 2: Eternal Blue): Yeah Lightning/Snow aren't one-rounding anything, while every single Concussion Sword Hiro gets off is potentially deadly. Honestly even if I did see Lightning+Snow one-rounding, a Concussion Sword + an Enchanted Kiss (or whatever)... that's three shots of effectively fatal status, one of those is going to land regardless of the statusblocker situation.
Hilda and Ricardo (Shadow Hearts: From the New World) vs Eirika and Ephraim (Fire Emblem: The Sacred Stones): Ricardo's evade-booster could grant Hilda a turn, but not like I see Grand Slam as turn 1 here anyway. So the twins kill Ricardo, Hilda revives him, repeat until the time Ricardo spends dead costs him a turn or one of the twins crits or Hilda runs out of MP? Yeah that's not working. So YOLO Grand Slam is the only hope, and even if that hits Hilda has to pray you don't see her as weak to monster-slaying weapons and... actually even if not will need to hit with Grand Slam next turn too, as revival gets her killed the turn after and leaves Ricardo vs. someone he can't beat.
Lulu and Wakka (Final Fantasy X) vs Riou and Jowy (Suikoden II): Ow. Best-case scenario is Wakka barely survives Hungry Friend and dies to Shining Light next turn. Pretty sure I see him being OHKOed anyway, though.
Lang and Sharon (Legaia 2: Dual Saga) vs Mesarthim and Zozma (Saga Frontier): 50% stun resistance + petrify immunity is probably enough here seeing as Mesarthim is not immune to charm.
Layna and Vitali (Soul Nomad & The World Eaters) vs Cthulhu and Umi (Cthulhu Saves the World): Uh... this is difficult. Should Vitali be in Layna's room or not? Mmm, never mind, no way he gets a turn in his own room, so he's in Layna's. But either way, it feels like an uphill fight for the SN team, as their typing advantage on male swordsmen + spears isn't that great (just a 15% damage cut for Cthulhu). Blind Strike is horrible for Layna, and speed-twinked Umi gets a turn for sure. Meanwhile, Vitali's still easy to kill and can't use field tactics. Layna can try to buff but isn't soloing this considering Umi's bevy of status options.