Pikachu use Thunder Smash

[Monkey D Goku]

^And then after we were told #16 had his bomb removed, Cell easily broke out of the hold anyways.

As for the other question.
If Ginyu swithced bodies with Gotenks/Gogeta, Ginyu would have a body that eventually splits up, so his soul would be evenly split between the two bodies, while Gotenks/Gogeta's soul would inhabit a body that isn't temporary.
If Ginyu switched bodies with Vegetto, Ginyu would have the most powerful body forever(unless he enters Buu insides without protection), but likely have problems figuring out how to utilize its power, while Vegetto would have a body that definitely would never split up unless he wills it to do so, but he would also be very weak...

I actually think nothing would happen to any fusion character that Ginyu tries to switch bodies with, like the fusion magic is a deterrent against that. It could also be the case of equivalent exchange as for instance Ginyu soul is not = Gotenks soul simply because Gotenks is made up of two souls. These are just my theories.

[Bussani]

There's an idea I don't think I've heard before: maybe Ginyu would switch places with one of them--for instance, Trunks)--and Gotenks' personality would become a mix of Goten and Ginyu.

Que everyone saying: "That can't be because I think Gotenks has his own soul instead of two inside him."

[Kid Buu]

Regarding the thread title, what does Pikachu have to do with any of this?

[Kaboom]

I'd actually think that the body switch wouldn't even work on a Fusion. If it's supposed to be a simple 1-on-1 switch, then the target body having two "souls" within it might prevent the technique from working if it doesn't have any way to choose one.

[Jord]

What's even more interesting is what would happen with Ginyu if he traded with Gotenks and the fusion time expires....