Official FF6: Beyond Chaos thread (randomizer)

Checking for something to absorb Flare Star is a good idea, as Vertigo said (EDIT: Your post came after I started writing this, I now know that you have no Fire element absorb). A rogue elemental absorption of Fire would make this pretty easy because he's heal you often when you attack. However, Magic Defense doesn't protect against Flare Star. Flare Star has its own special damage formula that only does damage based on your level (if your characters have higher levels, it will do more damage to you). Espers aren't given in a random order, so there's no chance that he has Palidor/Bahamut yet. Palidor doesn't sound like a good idea anyways, if Atma Weapon is going to cast Flare Star on each character as they land.

Atma Weapon's Speed shouldn't be a huge deal unless your menuing is slow or you are playing on Active. Usually animations take up so much time that each character should get to act once per turn of his, unless he just punches you. If you have no reservations about it, you could turn Battle Speed/Message Speed down to 6 and run to bring up the "Can't Run" message, delaying the ATB. This should slow down his attacks and make sure that each of your characters gets a turn in between his turns.

None of your characters should have Reflect, as you noticed. You can't leave people at low HP because of Flare Star, so you have to be able to use Cure 2 without provoking it.

Do you have any breakable attacking items? They could help to get some extra damage off.

Odds are that there's some way of beating him without having to rely on absurd luck.