This, I think in retrospect, was supposed to be a clue for Harry.  Harry was supposed to realize that someone used the baby as leverage, and so Harry was supposed to then figure out who knew that Justine was pregnant.  This is a small pool of people that probably only included Lara and Justine.  Lara can be immediately ruled out because of all the trouble this has caused the White Court, leaving us with ... Justine as the only suspect.  As Holmes says, "Once you've ruled out the impossible then whatever is left, however improbable, must be the truth."

Pretty weak clue. A lot of us thought in between PT and BG that the hit was the price of making a deal with something powerful to make sure the baby didn't kill Justine. Which was sort of a 'well, yes, but actually no' situation. Lampshading the inherent danger of carrying a whampire baby and saying he had a plan for that ended up being a distraction from the much more immediate threat that Nemesis could just make Justine jump out a window or something if Thomas didn't play ball.

I think there was a WOJ about whether the Paranet could sign up. Basically they'd have to win some fights before they'd build sufficient respect. Teaming up with the Librarians could help, but that's at best a long-term prospect since the Librarians are supposed to be really careful about not even being noticed by any supes. Plus, there's a national organization, and while the Paranet are centered in the US, they are to some extent trans-national - that's an additional dimension of obstacle.

Applying as a freeholding lord would also be tricky - the Council would lean on other signatories not to support him because it's an end-run around being expelled, and Marcone would exert similar pressure because signing up a Wizard of Chicago introduces uncertainty about whether Chicago is the territory of the Wizard or the Baron, and Mab's attitude toward it would be a coin-toss between liking a knight with a power base and disliking too much independence. 

Warden of Demonreach might have more juice to get recognized than Wizard of Chicago, but announcing that one any wider than it's already known is probably a bad move. He's not going to be able to sucker-punch anyone else too stupid or arrogant to realize the danger of imprisonment.

Maybe not every big bad...but I'd assume a fair amount of them. Particularly the earlier case files.
Also, SA, we have confirmation I believe of Sells and Kravos being infected. I agree they seem odd choices but I suspect the reasons for them won't be revealed until we find out a bit more about Nemesis.

Eh ... I wouldn't take Lily's list as authoritative. She was extensively misled.

There was a WOJ that the first nemfected character appeared 'on stage' in Grave Peril, so I think Sells is in the influenced but not infected category. I'm still uncertain whether he was talking about on the literal stage with Bianca at the party scene, or just on page in a general sense.

Yes a large caliber bullet to the head would (perhaps) kill the other WC vampires, but I think they are also in a totally different weight class than him.

Kincaid probably deals in ammunition that would do more like decapitation than hole-through-head, but Ebenezar possibly hates Kincaid even more than he does Lord Raith, so there's no way he's going there for a contract. Kincaid would probably refuse a contract there anyway on the premise Eb was probably setting him up to go on a suicide mission.

But Mab knew that, where Harry was, Molly was.  Mab won. The mantle was never in danger. The hapless mortal would have been Murphy, Justine was Maeve's ally.

Was Karrin even a compatible vessel? I think but for Molly, the mantle might have gone flying off the island entirely to some random changeling who'd been having sufficient contact with their Sidhe kin to qualify.

Does the Council know something about Mab that Dresden is clueless about?  Nemfected suspected?  Two people told Harry that a big part of him being kicked out was Mab.  Carlos said it started with Mab, and Eb said that him working with her was a factor. 
I know that Mab isn't a "good person", but to my knowledge she protects reality from Outsiders, ...  But the Council is against Outsiders so it shouldn't be a factor.

I don't think most of the council are aware of either the existence of Nemesis or Winter's role in defending the Gates. Rashid seemed to indicate that isn't shared with even all the other senior councilors unless they need to know, let alone general membership. Most of them just see the "Mab is not a good person" aspect.

I wonder if homes of things without souls have thresholds?  That would ruin that idea, but I think it worth discussing.

I'd lean no on that. The framing was always for human homes. Near-human species like forest people or whampires might be able to form a threshold (though I'm not sure the latter have fixed built homes, and the latter would presumably form extremely weak thresholds unless they're an unusual personality like Thomas').

have to assume he was planning on using magic, against the Rules.

Immobilizing someone with magic and cutting his throat with a small concealed knife is perfectly legal for the Council
. Or, for that matter, bashing his head in with any handily available rock.