only 1-4 and gogeta...
HA! I wish...
Lol ok fail.
You can't, because the SSJ5 level hasn't been officially created by Akira Toriyama (the creator of Dragon Ball). But if you really want to play against a SSJ5 Goku, you can search for a hack of Budokai 3 (NOT Budokai Tenkaichi 3, notice that) named Dragon Ball AF.
yes
Gohan ssj 5 but gohan was first who unlock ssj5 Then goku unlock ssj5
you basically cant its fake goku cant go further than ssj 4
you can go online and do multyplayer by bt3 Goku ssj 4
Yes
unfortunately No
If there were a SSJ5 Goku, he would theoretically be able to defeat Super Buu with a single punch.
Fight senron 5 times and go to the shop and they will have it for only goku
get all the way to gt saga and finish it then go to duel or what ever and go to gt kid goku and go to ssj4 goku or gogeta ssj4