The main theme is Harry trying to stay human and connected with humanity, from Storm Front where he openly advertises what he is through all the pop culture references, his desperate attempts to reconnect with Susan, his infection by Lash, his refusal to become the Winter Knight, his suicide attempt, it’s a constant battle for Harry not to become a monster, not become a peril for humanity, to stay human despite all the pain and loss and the offers of power and temptation.

You can’t compromise this about Harry, nor can you compromise the secondary characters important to this, Murphy, Michael, Will and Georgia, Butters, Molly, even Thomas whose battle against his inner monster mirrors Harry’s own, Uriel and Odin in all of his forms, Father Forthill. Everyone Harry looks to for moral advice and to stay grounded.

I think you have a fair point, but you forgot the other half - Harry's counterpoints. Sells, who goes mad with power. Marcone, who is kinda evil, kinda trying to do alright, and likely up for a fall. Nicodemus, who is a grade-A evil guy but loves it (and thinks his is the better path than Harry's). And maybe Cowl, if he ever comes back. Now you could probably mix away Cowl into the other two, but you can't have Harry's story without Marcone's and Nic's.

As I have said the real Battle Ground was in Harry’s head and heart, not Chicago and Sanya and Butters won. Their presence does make me wonder, was Lucifer lurking in Rudy’s lax trigger finger?

Ethnui’s presence in the mortal world would have mean’t the White God placing his champions on the field of Battle, Sanya and Butters, but also Harry to enforce his will in relation to no threats to reality which might threaten humanity. But could they really have been there for Harry?

Lucifer can’t touch the Knights, but Harry? He can turn Harry, he already tried once. Make a Starborn a Destroyer.

Eh. It seems to me this was a battle where Heaven and Hell were on the same side. After all, Marcone gave Harry the blood he needed.

The Kringle Mantle can be transferred on Halloween. It makes Kringle immortal, and Odin must die at Ragnarok.

I think that Marcone already has a list of who has been naughty or nice, at least in Chicago, and is checking it twice.

Just imagine how conflicted Harry would be, the self described Santa fanboy. It would be absolute torture, so that is a route Jim will likely take.

Torturing Harry within the confines of the story seems more his gig. Not with any random thing we can come up with.

Marcone might fit the Kringle mantle, as leader of the Wild Hunt, but he does not fit the Santa mantle as the great gift-giver at this time. He'd have to change too.

The Fallen need to partner up with a mortal being with free will, but not all wills are equal. Some are broken, weak and vacillating easily dominated by their Fallen. Others not so. We have seen Marcone’s will, he cannot be bullied, cajoled or seduced by a Fallen they would have to partner with him on less than equal terms, he can threaten to lay down his coin and he would do it, and place that coin somewhere humans couldn’t get at it for a very, very long time.

Lash started to get to Harry, by subterfuge, when Harry was aware of her he was able to get the upon hand and he changed Lash.

Marcone can dangle in front of Namshiel a couple of things, freedom from Nicky for one and the indulgence of Namshiel’s quest for magical knowledge for another. Both go with Marcone’s interests.

The big difference, of course, is Harry was sparring with a mere Shadow. Marcone has the real deal. I don't imagine Namshiel is anywhere near as easily directed as Lash.

Also I suspect laying down the coin would soon be quite hard for Marcone; he's getting older, and Namshiel will start keeping him going very soon.

Thinking about it Winter is all about sex and death, so Thomas finding a point congruent to a sex club in Chicago in Winter territory wouldn’t have been that difficult for him. He might have struggled in other parts of the Never Never but Faerie is the closest to the mortal realm and contains the majority of routes.

It does however indicate Winter probably already had an unhealthy fascination with Chicago before Grave Peril. Was Harry nudged there by Lea instead of going to say Kansas City when he left Hog Hollow because it was easier for her to stalk him there?

Aside from Demonreach, prior to Harry moving to Chicago  you had it as a residence of a Knight of the Sword and the Summer Knight (Ruel) who looked after changelings of both Courts a Supernatural connections. You also had it as a residence of the Raith family.

An intriguing thought, and something the Reds may have been noticing too; everyone was stacking agents in Chicago, and still is (see: Namshiel/Marcone, Butters, the Fomor starborn, the Titan, Svartalfs - but by now they may be drawn there by Harry as well as all the reasons why Lea may have nudged him there).

Uriel would be able to defeat Harry by unmaking the whole planet, but would be at risk if actually on the island.

I suspect many others have similar risks; stirring up Lake Michigan so the island floods would probably kill Harry, and even the Ladies could probably pull that (at least Molly could freeze large water bodies), but going into Harry's reach means you've mitigated most of such 'nuclear' options.

And of course, Harry is a mortal, so he has some advantages like circle traps. I wonder if Harry could use the island to empower a circle with his will, trapping anything overly supernatural. Odin or Drakul might be able to step out or smudge it for being just mortal-world enough, but not if they're wanting to go high-stakes magic combat right after (I assume, at least, that Odin has ways to store his powerups for later use outside of his person). Anyone else able to fight Harry on the island would definitely not be able to do it.

Well, except Lara could probably convince the US military to test some high-grade ordinance on that good-for-nothing empty island in the lake, why not?

The whole move together with Mother Summer implies to me that Faerie is ridiculously large. Else Harry could just find a route himself.

Or perhaps it's rather disjointed, with MS teleporting Harry along a particular route, Winter/Summer having alternative shortcuts that only the Fae take.

In either case, I would suspect the NN extends sideways a whole lot. We know Hades has a realm that touches reality, but I suspect it doesn't touch the Gates. When Ferrovax wants to Dragon around he probably has his demesne in the NN too.

So... Faerie and some others border reality. Faerie is big and mighty so it also extends to the Outer Gates. Others are wimpy so border only reality, and no doubt several realms usually don't really border reality, but can be shifted there by strong beings who haven't been Oblivioned (or by humans connecting with them).

   I really don't think it is a matter of how powerful Ivy is getting, the Archive always had that power.
  The issue has always been of Ivy controlling her emotions and letting the Archive doing what it needs to do.  I think that is what Luccio was getting at when she warned Harry about treating Ivy like a normal little girl at the end of Small Favor.

The Archive must inherently be conservative - after all it's fighting a war that takes centuries / millennia. What Harry was doing is push it/her to be active NOW, which is a risk, but comes with way more power expenditure.

So if Ivy gets out of the way and only the Archive acts, it will be careful to extricate itself from situations where she can show her power. But when Ivy acts, she stands up and shows what the Archive can really unleash in terms of direct power, as she did at the aquarium.

(the more subtle power of information, that probably works better in Archive-mode)