I am sure it fits nicely in your Mouse is Cerberos and Harry is Hades theory. :-)

You mean the one Hades himself pointed out to Harry intentionally?

"Fact" is a strong word that should be used carefully.  In one case we have the Knight Mantle going to the Summer Lady, in another we have the Winter Knight Mantle not going to the Lady upon the death of the Winter Knight.  I don't think we know for a fact what exactly the Mantle does or why, only some strong evidence that it goes back to Winter/Summer.  Even Titania thought Winter had somehow stolen the Summer Knight Mantle, so we don't know how exactly it works.

We don't, and do, Can't remember whom but someone said it goes back to the nearest reflection of itself... It being more or less a 'shadow' like Lasciel's, a bit connected directly to them, it would tend therefor to go back to one of them.... except if a greater mirror should exist that has not been identified. Though the table itself is kinda the cause of why the WK did not go to the lady or queen directly(which Mab was closer...)

I think the real problem is He didn't really know what he was trying to curse him with... He said it in spite so that he wouldn't die holding a coin, but also on other levels so he would feel the same loneliness he himself felt over the years and the bitter regret he felt at the particular moment. So the curse is less a specific thing and more a nebulas idea charged full of malcontent and negative emotions.

That...has some interesting implications. I agree that the parallel universe will likely mess with Harry's mantled state. Maybe while over there, like you say, he'll be cut from Winter and unable to access its benefits. It might even cripple him again. But unless something really weird happens, I think the agreement he had with Prime Mab (which would be an absolutely terrifying transformer) would not be broken just be moving from one universe to another.

Of course if Mab kept the current WK on ice during those years then only one WK would be exerting his will in reality at a time.... But Mabs never locked up her WK for the duration of any possible TT shenanigan books though, now did she

Oh, OH. lol, the real indicator there is that fortune is described on the list of the powers that be. Fortuna, Nemesis, ect... they are like comparing the greek and roman deities. Fate itself is watching Harry, be it the good or bad version imo.

Well Breath is used in:

(click to show/hide)

Zoo Day.  Mouse used it as magic.  So maybe it's similar to spirit/Chi something like that.

holy crap, that gives new meaning to anytime

That certainly seems like the implication.

While the narrative structure of nobody else understanding what Mouse is picking up because he can't communicate complex ideas to Hary or Maggie is cute for short story purposes, it kind of falls apart when we remember that Molly CAN understand him just fine. Dark, probably N-fected foo dogs working for probably Cowl and Kumori is something really freaking important to pass along, and ignoring that a suitable translator is around every week for family dinners at the Carpenter house would be a bit of a wtf? issue going forward if Harry stays unaware of it.

Or, hell, even Lea next time they cross paths - she'd be well motivated to continue checking names off her revenge list, if there's a lead on who gave her the athame.

Fairie, information, exchange....balance...

"... We're gonna need a bigger boat."

An aircraft carrier perhaps lol?