Y'know, I thought they'd might do something like that, but the answer is no. There is no incest in Dexter, save for that schoolyard bully joke (which is why I thought they were alluding to it).
She is pretty cute in her whore outfit. They've got a good cast of characters on the show. And I love how Dexter is completely alienated, but tries so hard to fit in. He's the most noble serial killer ever.
The very last scene in the season finale really sealed that for me.