I've found a quick fix for the offering. You can have it inflict confuse on your character. Then it's like a gamble, because it could annihilate the enemy or it could wipe out your entire party just as easily. The confusion can't be removed either, it stays even if the character is dead(at least the little spinning green circle thing does). It COULD be cheap now, but it is much more likely to be useless and even detrimental, especially since you won't have time to put your life 3 on if the offering character kills enemies first.

and i90east, your fears are well founded, I experimented with making custom monsters there and it does mess some things up. Most of those monsters are invisible control boxes of sorts. For example, there is an invisible narsh guard in the final battle which calls the forms of Kefka. Without that guard, the battle would end after the first wave of enemies dies. Collosus and Czar Dragon aren't used so you could make custom monsters out of them. Plus you could very easily remove Zone Eater,Cactrot,Doom Gaze,Atma,Hoover, and pretty much any boss and replace them with another boss and get a custom monster that way. The help is much appreciated, thanks everyone