here i will even help you see them
1.Shenron - Altough you are correct, it must have been baised on yours I will admit But look at the obvious differences, the horns, the size of the loop in the middel, the wiskers, his ears, so on and so forth
2.Goku - Take a look at his arms, no a really close look at his arms, thats the big give away they are not yours
3.Vegeta - the model hex made, his head is fatter then yours, his chest is wider, and his hips not as fat (like your head?)
4.Gohan - here is a semi better picture Taken by me ingame, the head is a dead giveaway, the hair is too short, the peice over his face is not the same thinkness, and his head is wider
5.Piccolo - ok this ones tough, ok so his head just like all the others gives it away, the antanas are different, the shape of his head is different
there, next time ill circle them for ya! ^_^