One way to deal some nice damage to Air Buster is save some Bolt Plumes from the first reactor. You can win them off those Sweepers, which when you encounter them alone, are fairly easy to beat. (And when you encounter them with others, you use a Bolt Plume to one hit KO all enemies, and you win another one off them plus EXP and maybe a couple of Potions).
That aside, back attack him with Limit Breaks. I do think Bolt is worth casting when you don't have limits, though. But only have one person using it, the other two should be ready to cast Cure as needed.
Really, I think my one piece of advice for this mod is don't underestimate white (healing) magic in it. Its usefulness is limited at best in vanilla, but it's very hard to live without here. You want Restore-All on everyone ASAP, and whenever possible put the combination into a double or triple growth piece of equipment, certianly never on a None (unless they're already mastered). Revive-All and Heal on at least one character is also pretty much essential, again, you want to be levelling these up ASAP. I wouldn't go out of my way to put All with Heal, but once you get Mega-All you may as well put Heal on the character you give Mega-All to. (This is mostly because against anything that can status everyone at once, you're probably going to want to be dealing with it via Resist rather than Esuna anyway, and Resist can't be all'd). You also want to learn White Wind as soon as possible; you can get away with dropping some of the Alls on your restores once you have it (but I'd reccomend still keeping at least one Restore-All combo, if nothing else for Regen-All). Do keep in mind that you still want to have Heal once you get White Wind, because in this mod White Wind no longer heals most status effects (except for Sleep and Confusion). However, if you're using Resist, make sure you cast any positive statuses you want (mostly Sadness, Haste and Regen, barriers have limited usefulness against bosses where you need Resist as they run out) before you cast Resist as it also makes the target immune to *positive* statuses too (Dragon Force and Hero Drink still work after resist, though).
...on that note, I actually have a minor technical question. If you cast Resist and then Death Force on a character already under Death Sentence, they won't die when the death sentence runs out... but what causes this? Does Death Force still work even under resist, or does Resist just protect against death too? (I always thought it didn't, but I haven't actually checked.)