Can I bend plastic hands?

You could try heating the hand in HOT water and carefully bending the fingers back, buut your best bet would probably be to score the inside of the hand at the joints and bend them back. When they are in the right position, apply a thin coat of superglue for strength. You may need to do this at he wrist, as well.

Sounds good, I appreciate that, I will give them a try!!

Any luck? If not, I'd say just pray to the model gods, offer some green army men up for sacrifice, and cut the finer off, then use some putty to help mold it back on.

I would look for a better hand rather than bending one... But yeah, what aj said... Scoring would be better than themo-forming here..