The Reddit write up didn't include my question that Jim answered. "Must the fae queen mantles go to mortals and does it change their DNA?"
Jim answered, Yes, and yes. Since mortals are the only ones who have free will, the queens must start out with free will. Which is odd, because we've already seen examples of how Molly doesn't have free will in all things, already.
Later, one of the other questions was about Harry's free will. Jim said that his free will is dependent upon how many commands Mab saddles him with.
I have an audio file of the Q&A. I intend to write a transcript, but I haven't had time. Perhaps I'll load it up to YouTube.