I have some questions regarding the advance purchase "deposit"

I booked one hotel in another country and accidentally "guaranteed" the room using the wrong credit card (one that charges foreign-exchange fees).

Since it's described as a "deposit", can I change the credit card on check-in or check-out for them to charge one that is free for me to use instead - and refund the deposit?

Almost the same question on a different situation:
I'm going on a business trip with a colleague who, despite me urging him to join priority club, doesn't care for the programme or points.

Good for me, right? I understand I can book his room under my account and collect the points (in the US).

However, same situation: I'd like to book a non-refundable advance purchase rate.
I don't mind putting down the deposit in my name, but for expensing the trip he should be the one paying at check out.

So can I get the deposit back when he pays with his card?

Any experiences are appreciated!