I want to freeze garbanzo beans- should I hull them first, or can I do that once they are defrosted?

If they absolutely have to be peeled, I would be tempted to do so first, so I know they are ready, but it's possible they might peel more easily after freezing.

You might be interested in this thread on chickpea freezing techniques: https://food52.com/hotline/4040-i-want-to-freeze-a-half-batch-of-cooked-chickpeas-garbanzo-beans-do-i-freeze-them-in-the-cooking-wat