1. Look for Drakul in the next book.
2. Harry buys a basketball hoop for the great hall with some of his diamond money (so, a few hundred bucks. What does he do with the rest of the cash?) What great hall? The one in the castle for sure. Which implies...
he gets the castle at the end
Also, interesting how one of the Merlin's after the original won the castle at Edinburgh in a bet with a Sidhe Lord...perhaps Harry will do the same with Marcone
3. The Fomor do not merely contain the Frog men and the rulers like Ethniu and Balor (although I suspect Balor is out or dead). They also contain (as stated in the books, but restated in a recent q&a) all the defeated monsters and gods etc. So I suspect we will see a MASSIVE bunch of creatures and beings from various mythologies and legends. But I doubt we will see anything on Ethniu's level...perhaps some demigods but probably not many. Giants for sure. That footprint on the beach wasn't Ethniu's I am sure (I worked out a bit of the math and that footprint would at least apply to a being about 16 feet tall and Ethniu is only 9 or 10 feet, as she is head and shoulders taller than Corb who is 8 feet).
4. The Tuatha are officially a part of the Sidhe. It seems like the Faeries incorporated the Tuatha or combined with them to form a nation. The mantles are currently held by the Queens and Rulers of the Fae. They range from powerful beings to demigods and full-blown gods. Mab is in the demi-god level (stated more than a few times in the series).
5. So basically we have known for a while that the Gods etc haven't been all that active. Some asleep, some imprisoned, some banished and some are dead. They basically haven't been doing their job (implied to be guiding and protecting humanity). It seems that the Fae are one aspect of what replaced them...but not necessarily the only one. Many of the gods (like Vadderung) gave up some of their power to go do other things. This also all ties into the next WOJ.
6.
MAJOR SPOILER So a fan asked how do all the various gods and pantheons work considering they all have different and contradicting stories of Creation. Jim said that basically Creation is very difficult for mortals to even comprehend because it happened in a time before time existed (itself a contradiction). So there was this moment (I assume the Let There Be Light thing) that formed Creation and all the gods and beings who were there only sort of remember it, because all their memories are literally not in order (no cause and effect, no actual sequence to them) and consequently only really remember when they are reminded. Jim likened it to a great big party where everyone got drunk and only remember what happened in bits and mostly only when other people remind them. If you can grasp the concept it is pretty cool and hilarious (I say this not because it is necessarily difficult, it's a clever bunch we have on these forums, but because I probably haven't explained it well). He also through in a teaser that Lucifer rebelling and the War in Heaven also has something to do with the contradictions...he sort of implies it happened right after.
7. He gives confirmation (of a sort) that the Dresdenverse reality is much like the Chronicles of Amber i.e. a spectrum from absolute chaos to absolute order. This is when he is asked if Harry could get to Alera. Interestingly, he has stated this before (both from Bob but also in a separate interview) but never confirmed about the spectrum from absolute chaos to absolute order. As has previously been guessed at but not confirmed before, the Outsiders appear to come from the chaos end. I say this because Harry states that beyond the Outer Gates is elemental chaos, which he hasn't said before.
8. A fan crack theory was good enough to influence Jim. At first he rejected it but then he went "I could work with that".
9. The line of succession if Mab dies isn't as clear as you might think. But it would be a
bad thing.
10. Maeve and Sarissa were named thus for a reason. Mab wanted her children to be weapons. Draw your own conclusions.
11. Cowl...he refused to answer knowing that no matter what he said or didn't say it gives away something. He seems to imply (at least to me) that Cowl will return soon.
12. Ghosts are not souls. He completely separates them. He says ghosts are energy beings in the shape of humans with human memories, not that they are human souls. This has been the subject of some debate in the past but he couldn't be more clear.
13. Ectomancy and Necromancy are not the same. Ectomancy is communicating with ghosts and seeking knowledge, and binding them occasionally. Necromancy plays with life force. Yes, you can simulate some effects either way but Jim says Necromancy is very different.
Anyone heard anything else or picked up anything that I missed in the interviews?