1.  Nic is trying to get something to regain the loyalty of the Denarians.  Most of those that were loyal to him have died in recent conflicts and their coins possibly held by Tessa.
2. I am betting there is a specific trap to Hades vault that requires a mortal (churchmouse), and another that requires a mortal+ (harry).
3.  Nicodemus will almost definitely recruit Rosanna, I too believe that she will make a choice.  I am torn as to whether that choice will be killing Sanya or dying in his place at some point in this novel. 
4. It would be great if Harry were forced to choose Fix.  He could learn more about the mantles and Fix could go off on his own attempting to resurrect Lily.
5. Sanya will be present.  Michael will help Harry pick a replacement for one of the swords.  Probably Fidelachus.
6. Mab hates repaying favors in ways that she doesn't wish too.  Nic delights in calling in favors that pain the giver.
7. Lash, This whole book is greek mythos.  I wouldn't be surprised if Skin Game is partially a play on getting skin for Lash.
8. Odin is trying to get the greek pantheon to be more active.  Poseidon could do a number on the fomors if he chose to. (edit) I think the twist might be that Nic is trying to put Denarians he can't trust into the vault.
10. Harry will specifically refer to one of the denarians we have not seen before with abilities involving a swarm of rats, The Rat Pack.