Toot painted his face half blue when Harry became the Winter Knight in Changes. He said "We are Winter now".

It could come down to individual bargains and relationships, just as in medieval feudal society. A simple peasant or soldier was directly related to his lord. The lord was in a direct relationship to a duke e. g., the duke then to a king and so on. By these indirect links, the king ruled the whole country.

Things like Kringle being Vadderung with different relationships to Queen Mab were not uncommon at all in the higher aristocracy. These guys held several titles. The king of one country could own a duchy in another and technically be the vassal of someone with whom he was otherwise in an equal relationship and maybe even be at war with him.

Actually I believe Harry was only nineteen or twenty when he left Eb.   He was 16 when he was sent to live with him under the Doom and stayed for three years..  Not sure if he traveled around a bit or just when he studied for license and went to work for Angel Detective Agency and settled in Chicago.  If I remember correctly in Storm Front Harry is twenty five or six..

Yep, I think it was confirmed in a WoJ that Harry was about 25 or 26 in SF.
He was 16 when he went to Eb, stayed there for 3 years, travelled around almost a year then went to Chicago. So he was about 20 when he became Nick's apprentice. The apprenticeship lasted 3 years, then he got his own office. Which he had for 2 or 3 years in SF.
Lets assume Restoration of Faith happened during the first year he was with Nick. Faith was 10. So she was about 15 in SF. That's about the age that magic can manifest. Assuming Cowl was the one who corrupted Victor Sells, he might have been around Chicago and met Faith. Cowl would only have taken her as an apprentice (rather than just corrupting her and see what flew up as he did with Sells) if she had real potential and was ready to take the left-hand path. Lets assume she was.

She was at Bianca's party with Cowl. Age 17. Not impossible.

In Dead Beat she would have been 20 or 21. That's also not impossible. The only one who saw part of her face was Lamar, the paramedic. He said she was white. Nothing about her looking a particular age.

Cowl and Kumori talked in English, even when they might not have wanted Harry to understand them. An older wizard might have picked up a language or two that was not so commonly understood all over the place.

Kumori's belief that Necromancy might be used for good is rather naive. Also fits a young person who got trained by a bad guy. And she was the one who tried to not kill Harry several times. Could be because he saved her once and introduced her to the world of magic in the first place.

The only complicated bit of magic we knew she did was the resurrection of Marcone's man in Dead Beat. Which was a bit stupid to do because she exhausted herself in a critical situation to save a criminal. A more experienced wizard would have had other priorities. This also indicates that she can't have understood the consequences of the Darkhallow - the guy she saved would probably have died anyway.

Will she be Cowl's apprentice?

I like her for Kumori a lot better than Elaine. The only issue would be age. She was ten in "A Restoration of Faith" iirc. The timeline places her age during DB at about 18, which would be awfully young for an accomplished apprentice. But I think there's some room for her to be older, because Murphy was a beat cop during the story. You don't become Lieutenant in 3 years.

It's always been a bit of a mystery why Mab tried to save Marcone in Small Favor, even before he was actually attacked to boot, and I think I might have an explanation that's both logical and doesn't give Mr. Occam too much headache.

Maeve was involved.

Mab knew that Nemesis had gotten Maeve. She wasn't ready to kill her just yet, but she sure as hell kept tabs on what she was doing.

So, if Maeve was active in Chicago, Mab took notice too. Hence the snowfall. It couldn't have been obvious to her what exactly the plan was, so she decided to spend a favor to hire Harry and had the new Accord member under observation as well. Maeve wouldn't have liked that much, so she made sure that Titania knew about Harry becoming an Emissary of Winter, making him a legit target for her revenge. There might be someone Nemfected left in Summer after all, after Aurora. That's why the first move from Harry's pov was from Summer's Emissaries, trying to kill him. Ironicyally, it made Mab's job to convince him to take it up a lot easier (ok, maybe she engineered that herself, wouldn't be the first or the last time she puts Harry in a corner to get him to do her bidding). Anyway, Marcone was abducted by parties unknown to Mab. She said so explicitly when she showed Harry the snow model, so she didn't knew at that point in time who else was on the enemy team. Harry finds out and gets the Council involved and everything ...

Here comes Maeve's most likely move (imho): Catching the Archive at the train station (or maybe at the place she intended to stay) before Nicodemus could lay his hands on her.

Mab figured it out just in time. She realized that she had made a mistake in assuming that Marcone was the (primary) target Nemesis/her daughter was after. In a desperate attempt to prevent that, she sent the Hobbs, taking the risk that they killed the current host of the Archive. The Archive would have gone to the next person in line and been safe from Nemfection.

Harry (with Uriel's help) did the rest.

I suppose that conversation Ivy had with Mab was somewhat awkward.

When Justin got Bob (hereafter "proto-Bob") he too was attacked by a creature whose had been "twisted" by kemmler and had to Order the SoI to Forget some and suppress other Knowledge/Memories of his time with Kemmler, just as Harry did. The only difference is that Justin actually cared about saving the secret arcane lore contained in the SoI, so his order didnt go as far as Harry's did and left the "pieces" that harry woke up in DB. 

This makes perfect sense. Justin wouldn't want to lose the knowledge permanently, so it was there, but Bob was ordered to suppress it. Harry was the one who told him to get rid of it, so Bob was free to lob it off after Dead Beat.

I envision Harry digging through the ashes looking for Elaine's body, finding a skull, touching it, and discovering it talks.

If he never saw Justin speaking with the skull, it's personality but would be almost entirely the imprint of Harry's teenage subconscious.

That's what I think too. When the Wardens came, Bob must have told Harry to hide him. Harry probably got back to get him after he left Ebenezar.

Eb on Rashid's role:

Likely he knows already. Knew already. Maybe even pointed you in a direction that would show you more. Assuming he wasn't simply using you to poke a hornet's nest and see what flew up.

How so? Because he has a bigger will and a direct access to the core of their being? and yet his daughter plots to overthrow him... don't mistake a compulsion for a lack of will. You can do pretty much the same thing and worse to any human with the right connects.

Well, exactly like that. The compulsion is relevant because it's built into their nature. Not having free will doesn't mean that you can't have desires and thoughts, it means the Red King can set the law and force the Ramps to act according to his will. Because he is their progenitor imo. They can't not obey. His daughter has to plot really carefully to overthrow him. The compulsion seems to come from the blood connection, meaning that the Rampires higher up in the family tree are automatically more powerful and can compel their "children". We've seen hints of this as far back as GP, where Bianca controls her household of freshly made Vampires.

The same as Molly not being able to act against Winter Law or a direct command from Mab.

Also consider Bob, he has no free will so he can't act against his nature. Doesn't mean he can't try to strike deals with Harry or not like a particular command. But he can't disobey a direct command from whoever possesses him atm.