Theres a few WOJ on the subject.
1. That there was one Mother Summer before our current one:

1. the mothers - how does a queen become a mother? like after a thousand yrs, old winter dies and mab becomes the new mother?
Essentially abdication.  The previous mother wearies of her duty and moves along.  There's been one new Mother Summer during recorded human history.  Mother Winter has never retired.

As for the nature of Fae Mantles theres a bunch:

if the Ladies become the Queen, what happens to the Mothers at that point? The thing is that the Mothers are kind of the foundation.  So, it’s not so much what happens to them because the little mantles changed. It’s what happens to the little mantles if the big mantles change. So, if someone whacks the being that is, for all intents and purposes, Baba Yaga, and then Mab succeeds, then Mab becomes the new Baba Yaga, and Molly gets drawn up to Mab, and they have to find someone else to become the new Lady. But on the other hand, the Mothers are extremely powerful beings

So there's that to chew on.

As for theories. Before the Fae it was the Greek and Norse gods and mythologies that protected the Outer Gates. Is the most commonly accepted theory.

Personally I think it was Dragons before them, but thats just my WAG.

Ref:  https://www.paranetonline.com/index.php/topic,50129.msg2289460.html#msg2289460

  I put out the theory a while back that perhaps Justin and Margaret LeFay were working together to learn how to create a starborn.
  This idea explains how Justin was able to find Elaine as well as Harry.  Both are powerful and skilled wizards, it is not believable that Justin could have found two such apprentices by chance.

APG

It's a common theory. Along with Maggie being the main recruiter of what we know of the Black Council, Black Circle and Black Hats. Or atleast being crucially involved.

But yeah that is what Maggie Sr and Papa Raith were working on is a common theory. Definitely seems likely that Justin was specifically able to track and train Starborns.

While Justin didn't have contact, there was a "nice
lady" who did, and that was Lea.  She'd have the power to wall Harry off, but why?

The thought just came to me that since he was a star child, Lea knew that there were enemy forces out to get him, so she kept him hidden.  However it would be hard to hide the fact when his powers began to awaken.  Why she let Justin have him is anyone's guess, but even she isn't immune to making mistakes.  I doubt she was on Justin's side or knew fully of his intentions otherwise she wouldn't have helped Harry get ready to kill him.

Lea thinks that Justin was a great teacher, using pain and emotional manipulation to forge him into a weapon. It's kind of her thing.

I mean the last traitor came out of nowhere. Peabody was a minor character, nobody suspected because people thought he was useful but insignificant. Ebenezar and Harry even had a list of suspects who knew about the boot camp and had dismissed Luccio as a suspect. Therefore both actual traitors were dismissed or not even thought of.

Fortiers replacement was never even heard of until he took the council spot.

I'm not saying we haven't met who the other traitor(s) might be. I'm saying the last one came out of left field. For all we know it's Chandler.

It's a good theory.

I like the theory, Con.

Thanks guys

It'd also help explain the rivalry Lana and Marcone have. Friendly rivalry as far as murderous factions go.

Ok so admittedly I've been watching a couple of Michael Franzese's videos on youtube. Some first hand statistics he gives is that in 1986 he was cited as one of the top 50 mob bosses in America, by today he's the only one still alive.

So Marcone being on top for a couple of decades in real world is fairly unlikely. So I have a WAG, that Marcone in addition to positioning himself within the Accords, has managed to convince some of those human US factions we here about in the background to let him be the Unofficial Ambassador to the Supernatural factions.

It would secure his position as being all but impossible to prosecute, as he's too vital for the role he plays. Lucky Luciano and a few other Mob bosses had similar deals in WW2, or against Cuba.

This would be beneficial to the Nation not only because he's the only pure human on the accords, but also as a measure and step against Lara Raiths increase in power as well. As Thomas says Lara wants control, and even by Changes was able to bring a chopper into Mexico. Laras power has really only grown since the Fall of the Red Court, and the loose alliance against the Fomor.

Marcone would be seen as the devil they know. Even Harry views him as such.

So thoughts?

I like it. It's a good Dresden based theological breakdown. My one caveat is that if Lucifer is Spirit and wizards rely on spirit for their magic, it gives credence to the idea that they're all devil worshippers. Which while might explain in world persecution of magical users, as well as Michaels initial reluctance towards Harry himself. Would seem to go against the beliefs of the Wizards themselves. Harry and Rashid particularly. Harry believes Magic is pure aspect of creation of life, to be used to protect those in need of it. Rashid is Muslim, and probably has similar beliefs regarding the Outer Gates or the Ways of the Nevernever. Admittedly I have a vage notion that some teachings of Islam include, that Lucifer and God aren't necessarily archenemies, I don't know enough of it too (respectively) make a case.

The fact that Eb wrote in his journal that Harry was one of a few Wizards he'd trust to the job of Warden, would seem to suggest he knows Harry can fight Outsiders.