Ok you say that you have bought all the unlockables and you only have 1 challenge left which is the Rumble challenge. I remeber this very well and i agree it is very hard but the trick for this challenge is, use Andre The Giant. Andre can lift anybody exepct Super Heavyweights, so you pick to be Andre and make everybody else in the Rumble match a Heavyweight or lighter. I havn't played this game for ages cause I lent it to a friend and he STILL hasn't given it me back after a few months, but I think its any directional button and the O button to pick somebody over Andres Head, then it's O or [] to throw them over the ropes, If anybody remebers the contols for this trick then post them cause I forgot :S
p.s if your having trouble picking people up over Andre's head then throw them over the rope so they are standing on the apron and press O and a Dirctional button, that will get rd of them no matter how much is left in their ring out meter
HOPE THAT HELPS!