Honestly, there are so many people complaining about things being hard/unfair that I might write a full-on Official Prima Strategy Guide (TM) for this. I actually beat Catzilla on my first try, powered purely by spite after TheGeeb81's vicious rant.
Hunter can suck a Cactuar's ballsack, though. He's the one I'm having the most trouble with, funnily enough. I have a *theory* as to how I can take him down, but it's both incredibly tedious and incredibly risky and RNG dependent. There's gotta be SOMETHING I'm missing, but, as far as I can tell, he ALWAYS flashbangs on the first turn after you kill all the other enemies, which *seems* to be the only way to make him vulnerable. My working theory right now is that you have to get lucky and spawn him in a formation with a Drain/Shield type enemy, then bait it into putting Barrier on itself and using an AOE attack, which basically means it has to be Invoke->Judgment. Dragon's Throat *might* be plausible, but it does so little damage, even with the DOT from Burning, and the fact that it overwrites a Stun makes it extremely hard to justify.