I gotta agree with you that it's hard to do this kinda thing without a larger following, unless your comic revolves around it! I've seen some comics set up as a kinda choose-your-own-adventure type deal, and those can get engagement, but they kinda have a different set-up from the get-go.
I waited to do any Q&A/audience feedback things until the point that people were asking me stuff on their own, without me prompting it. If you try to get audience participation, and people don't already have stuff they wanna see or ask, you might get a couple people who try to think of something to suggest, just to participate, but in my experience it's hard to sustain that!
To be totally honest, this would have the opposite effect on me! When I see artists start to do "hey guys tell me what to draw!" type strips, it makes me wonder if maybe they're running out of ideas. When I follow a funny comic, it's because I like the cartoonist's sense of humour and the ideas that they have make me laugh. Some random other guy's suggestion of what would be funny is probably a lot less interesting to me.