And because there is a confluence in Chicago -- all of the same "dark powers" that Harry noted are still coming to bear, there -- I think Michael will more-often be Guided to Murphy's aid, than he originally was in the first few books.

Or not, Michael wasn't guided to her aid in the first few books..  I go back to the original assumption that everyone seems to have, and since I don't keep up with them I don't keep up very well with WOJs, is the other Harry is an evil counter point to our Harry.. If nothing if changed because of that, shrug of shoulders, Harry in the other universe is evil..  However I don't think so.. If one goes by "It's a Wonderful Life," all matter of things go wrong because our hero was never born... One prime example is at the age of 10 he saved his brother, who grew up to in the Medal of Honor because he saved hundreds of men on board a ship if I remember correctly... If he hadn't been saved, then not just he would have died, but the hundreds that he saved would have died, and maybe hundreds more children who would have done great things were never born.... It goes on and on like that..  It isn't about the now evil Harry, it's about the wrong choice that was made that really screws things up in both timelines.

It's in the chapter immediately following the one where Susan dies; Harry talks about the fallout from the destruction of the entire Red Court; so, not in-the-moment stuff or stuff Harry personally saw/experienced; but Harry telling us about things that he heard of, broadly.

That doesn't mean anything as far as something "human" remaining in the fully turned.  Bianca the main example we have was full
RCV, nothing human about her, but she appeared human to the eye and could be very charming, so could others in the world, but that doesn't mean that anything human remained of them...

So long as he wears the Kringle mantle, he's subject to Winter.
But he appears able to put it on and take it off at will.

More like an associate of Winter or with Winter, I doubt that Kringle would take a direct order from Mab for example, or that she would give one.. I think they actually agree on a lot of stuff, I also think because of his multiple mantles that he is way too complex to be a subject.

I believe that there is an old WOJ that states that Lara's control of the White Court is slipping because Papa Raith is becoming more unstable. We know that some of Twelve Months will be dealing with the White Court. I think it is conceivable that there will be a loss of control of Papa Raith and Harry will have to help Lara set herself up as the White Queen. She will no longer be ruling from the shadows. This could dovetail nicely with a hunt for Outsiders in the White Court that other posters have mentioned.

No hint of that so far, however we haven't heard a word from the other branches of the White Court since "White Night," so it is possible that the Raith family will find itself on the outside looking in.  Lara may find herself with her father incapacitated, Thomas and Justine now gone, isolated and she may have to turn to Harry, and not from her usual position of strength.. Or with the help of whatever is protecting him, Papa Raith makes a huge come back, plus perhaps many in the family didn't like the fact that she chose to fight against the Fomor in the battle for Chicago.  Then there is Toot and Za'Gard, they haven't forgotten their treatment at the hands of the White Court, I doubt they will remain passive in all of this.

It would be interesting to see how Kringle interacts with the Mothers.  JB said at one point that pretty much everybody in Faerie is subordinate to the Mothers, but is Odin?  I mean he's not exactly 'of Faerie' in his own identity...

I doubt that he is because he is a "god" in his own right.

I thought it was heavily implied that the Reds capture people of importance and 'turn' them, then allow that person to return to their former position, now fully influenced and controlled by the reds.  It is mentioned in Changes that a ton of politicians and business leaders all died/disappeared at the same time the red court died.

I don't remember that.. However just because they appear "human" that doesn't mean that they were anymore.. Again, Bianca is a prime example of that, when stressed by Harry's sunshine hanky, she reverted to her true from, that ugly bat creature.  Susan as well, once she transformed into full Red Court Vamp becoming the youngest, when Harry cut her throat she was no longer human.

Of the half turned, once the vampire part of them died, if they were young enough the human survived, but those too old simply died.

You forget:  Michael has some extra guidance! 
Without Harry's assistance, SI & Murphy will have needed some extra help... help that Michael is well-situated to provide!  Obviously, that's no guarantee Jim will have written it that way; but it'd be  a nice exemplar of God's Providence, with Michael's multiversal presence situated to support Murphy (or in a different Alt!Universe, Morty?) when that alt!Harry does not.

Unless Murphy is closed minded about the supernatural, there is no guarantee that she'd be receptive to a so called "Holy Knight."

I don't see any way for Mirror!Murphy to have buried her head in the sand and deny the supernatural; and Harry will *very* much be on Mirror!Murphy's radar -- as a Bad Guy(tm)!

Actually you make my point very well.. Murphy sees things in black and white, if all she sees is an "evil Harry" how do you think she will see the supernatural in general?  Also remember how quickly she was to jump to conclusions in the first couple of books because she did not understand Harry's world at all.

Early-books Harry was still giving Murphy lots of stay-alive info (albeit limited/incomplete), and I expect that didn't stop completely when he made the Choice.  Remember that Murphy got so deeply into the supernatural because of Harry.  Without Harry there, opening the doors he opened, Murphy's likely to have had shallower, less-dangerous encounters.

Alternatively, maybe Mirror!Murphy teamed up with Michael, who -- while (mostly) not as clued-in as Harry -- had much more info than Murphy!

Or closed minded, and why would she team up with Michael?  I doubt without Harry she would have even known Micheal.  You forget even in this timeline she got a Holy Sword broken because she felt her judgement was better than God's Judgement when it came to Nic. 

For the record?  If you really want to torture Harry, have Murphy act like he never existed, and treat him that way as well with a totally closed mind towards the supernatural...  Oh and maybe still married to one of her husbands...