Looking through the WoJ section I found some bits and pieces that might allow us to add a little to our knowledge of what's coming next.
Someone asked Jim, way back in 2011, when we'd see Injun Joe again. Jim replied, "Injun Joe will have to be in there by [pause to think] at least by book 15. Probably 15 and 16, he’ll both be in. [pause] Yeah, that seems about right. I have to think these things through, I haven’t thought of the answer to absolutely every question."
So Peace Talks is book 15. I could see a role for him in Mirror Mirror too.
When asked if we'd see Agent Tilly again, Jim replied, "Yes definitely. Tilly I had to get into the story a little bit earlier on, for when things are happening on more than the Chicago level later in the story."
Damn that's pretty vague, but it sounds like Tilly is coming back eventually, but probably not in Peace Talks, but I'm not really sure about that guess.
After talking about Mirror Mirror a bit in 2014 Jim said this:"There’s Skin Game and then the next one the White Council is going to come to town and there’s going to be a big brouhaha, and then I think I can do Mirror Mirror after that. And then maybe we’ll do professional wrestling stories. Because I love professional wrestling. I watch it for the writing. And you can sort of pick out, well, wait, what’s the inspiration for this show? And you can figure out what the book is the inspiration for this show, this particular segment of the wrestling. It’s like, ‘Ah ha! This is the Return of the King episode. Look! They’ve destroyed the evil guy and now the good king is back, and now he’s the champion of the league, and so and so has been fired, and so and so has been re-hired, and he stretched forth his hand and cured a girl of cancer.’ It’s wonderful. I love watching wrestling. It’s great fiction."
There was actually more interesting info in there about the wrestling book than Peace Talks. However, I can make a guess about Peace Talks if I add in that Jim recently said this book will get apocalyptic. Perhaps more than just a couple of representatives and bodyguards from the White Council will eventually become involved in the story. My guess is, at first there will be one or two senior council members sent as negotiators with a retinue of security forces, but when the situation devolves into something uglier, this will force the White Council to commit more forces (more senior council members); or at least the Senior Council will justify their actions that way. I also remember the post Peace Talks, Christmas Eve story where it's mentioned that Harry tried to warn people that things could get out of hand. It wasn't said who Harry warned, but it seems most likely that Harry would have warned the Council, probably Marcone and maybe Lara Raith, that their actions could have dire consequences. I don't think Harry would warn Mab, because he'd know that she wouldn't care. Mab's going to do whatever she thinks is necessary to get the job done.