couple problems
i think the flash work done is very good but there is a vew problems
1.gohan doesnt have to turn mystic
2.gohan was absorbed by buu at this point so was gotenks
3.vegito cant power down once he goes ssj
4.gohan cant go to ssj when he is in mystic form because it wouldnt result in a power up
5.vegito would destroy both of those two in 5 seconds