I only read the first two books and even then the TV series was way off the rails compared to the books. I doubt there is even a baby in the book series.

Quinn might as well stick the knife in Deb's heart now. Maybe him knowing how she feels about him will make him have change of heart about his investigation about Dexter?

It occurs to me that one interesting thing that they could do with Quinn is have him find out Dexter's "secret" and either let Dexter keep on doing what he's doing, or even actually end up assisting him... Dex could use a wingman considering how sloppy he's gotten lately...