about the SS3 goku thing, it is hard but i found out a little glitch thing that works, just stand COMPLETLY still and hold the block button.
oozaru vegeta is pure luck beating him, L1 lock off and run away, and if you can't do that fly up and kamehameha him, it is really hard and can take awhile to beat.
also I have all of the fusions in my FAQ, check it out sometime if you need to
for ss3 goku/kid buu.....just simply fly n run as quick as u can then charge n when u can shoot full power energy...do so....if ur under attack by buu dont block....try to move away(using x-button) on his side/back n attack him keep punching him till he goes down...the main key is u must stay mid air coz when he's down....u'll hav d advatage....that way u can last 4 90 sec
once u gathered 7 dragonballs u can make 1 wish at a time...where u can wish 4 character(special) or d password or a new z battlegate stage....u pick 1 choice each time u collected 7 Dragonballs
for hercule/kid buu.....it would b hard but u must stay away from him n run as much as u can....fight back if u must but u wont stand a chance fighting.....so u need to run n stay away till the time lapse
all these r things i did...i dunno if sum1 else hav a better idea...