Out of curiosity (since I don't have any closed questions), is it possible to accept answers on closed questions?
2 Answers
Yes
Yes, you can still accept it, and answers can still be voted on by everyone. Other users can also vote on your question.
Only locking prevents these actions.
Source: Can an answer of a closed question be accepted? [duplicate]
Yes, this is possible (see @DavidPostill's answer) and moreover, it happens quite often. Here are over 2,500 cases where a Super User question was closed and an answer was accepted next day or even later.