Why bother buying them out? Most of the fighters aren't good enough to be in the UFC and the ones who are would have no where else to go to make good money.
If the UFC feels like buying them, they will.
I am not seeing that happening right now, but if Bellator's ratings and incomes drop even more, they will run into big problems.
If the UFC make a good offer, it will happen.
...Or like you say: if Bellator won't generate the money they need to pay their top fighters, they may end up losing them for free.
Annyway there are some fighters i would love to see in the UFC or the new Strikeforce (or whatever the UFC will call it): Alvarez, Curran, Imada, Lombard, Askren, Hornbuckle, Warren, Freire, Sandro, Soto.
The others i don't really know that much.