Not really. 'Disguise' is a 'false friend' between French and English. We don't use this word in the same way as you use 'se déguiser' in French. People only disguise themselves if they are on the run from the police, for example. The usual expression to translate 'se déguiser en', in GB English at least, is 'dress up as..'. So you could say: 'What did you dress up as?' 'I dressed up as a witch. And I dressed the kids up as pumpkins.' You could also say: 'What were you dressed as for Halloween?' 'What was your Halloween costume?' or even: 'I heard you went to a Halloween party last night. What did you go as?' 'I wanted to go as a vampire, but it didn't have much time to get my costume together. So I just put on a white sheet and went as a ghost.'

And I add a question: What about, "What did you disguise as for Halloween? "

Sounds a little awkward. Why not try: "What did you dress up as for Halloween?" or "What costume did you choose?"