I'm reading the end of "Small Favor" and I just hit what looks for all the world like a patch of fairly obvious foreshadowing for next April's book.
This is pure speculation on my part. I don't have any spoilers along these lines. But, well ... see what you think.
Harry's talking to Mab at the end of the book, after she's been messing with him "for his own good".
"Not having it could have gotten me killed, too," I said. "And then you'd have wasted all that time you've put in trying to recruit me to be the next Winter Knight."
"Nonsense," Mab said. "If you died, I would simply recruit your brother. He would be well motivated to seek revenge upon your killers."
Because ... what else has Mab done, but just stated her contingency plan in the event of exactly what happens at the end of Changes?