MC banged his sister, his aunt and his mom. I don't think anyone will be surprised by him and Mia becoming a couple, with the exception of the dad.
Well, I suppose I should have clarified I meant a return to their
home town (where 'family reunions' tend to take place), not just a return to where they have been living recently with their aunt. If you don't think "anyone will be surpised" if siblings return to their home town - where many people have known them since they were kids - married with a baby, I would have to say you may have grown up in a very unusual town.
I agree there would probably be little reaction if they went back to
where the aunt lives because nobody knows them that well there (and may not even know they are related). I also doubt that given the circumstances they would ever move back to that hometown permanently to live there, but they
might travel back to visit under specific circumstances, and if anyone spotted them word would probably spread quickly given the salaciousness of the gossip, and some interesting consequences could ensue.
I'm thinking a grandparent falls ill and is hosptalized, so they come back in case it might be the last chance to see that grandparent alive, and one or more of their high school classmates who works at the hospital spreads the news from there... If I were a fanfic kind of person I would probably already have written it myself because I'm getting worked up just thinking about all the possibilities...