No Espers can be used
Magic that is learned naturally (Celes, Terra) is allowed (i think)
Gaus Rages are allowed
any equipment is allowed (i.e reflect rings)
Gogo is prohibited from having magic
magic-related attacks (i.e FIRE dance) are allowed
i'm pretty sure stragos lores are allowed
now, you may ask how the hell do you beat the fanatics tower? well, someone at the 'moogle cafe' board, where i first learned of the challenges, figured out a way. buy four reflect rings. take mog for his moggle charm (cant be attacked) and Gau, coz he MUST be able to learn life3 off a rage. now the magi master cannot hurt you, and Ultima will not kill you if you use life3! simple, no?
there is also something called 'munkwunks iron man challenge' i'll investigate as to what that is later...
one other interesting one is the 'first weapons' challenge. you are only allowed to use the weapons that you start with at the very beginning of the game, so you cant buy weapons at all. i'm also pretty sure that you cant buy relics either, so this really is one for the elite players only
