Don't make this too complicated, people. I'd be shocked if there was anything fishy going on in the narrative structure (e.g., a dream). I could be wrong; but I was mostly right about everything else this season, so that's unlikely (see post 34 in this thread). I'm talking to you, David.
I think Andy's questions/guesses are pretty good. I wouldn't be surprised if the older kids go to the grandparents and Deb moves in to help with the baby (and further enrich her relationship with Dexter). I don't think Dexter has to own up to sh*t, though. He's a high-profile person and could, reasonably, be targeted. Hell ... just look at what's happened to Deb in previous seasons (e.g., Ice Truck Killer). That said, it wouldn't surprise me if someone (Quinn) started snooping around/asking questions and Dexter has to do something about that next season.