Everybody assumes she met Malcolm after the meeting, when the safer assumption might be to assume she met him as a result of the meeting. Holding open the possibility that meeting him was what broke her free of Raith. I've always thought the possibility that she was pregnant when she ran was high. By the time she became pregnant she had fallen in love with Malcolm.  Since she knew when the baby had to be born to become a Starborn she entered Faerie and manipulated her time there to make sure the pregnancy ended at the right moment.

I have to go back and read the passage, but what I remember is Eb had dinner with Raith and Margaret from time to time..  Something a bit more casual than business, observing how Eb and Margaret interacted tipped Arianna off that they were father and daughter. Why would Margaret have met Malcolm as a result of having dinner with her father, Lord Raith, and Arianna?

Lash in White Night tells Harry that his mother found the strength to leave Lord Raith for a reason.
That reason was Malcolm, she had fallen in love with him and because of his goodness decided to conceive a star child with him.  In the soul gaze with Thomas when he talks Margaret, she says she is sorry for the burden she and Malcolm placed on him.  In his dream conversation with Malcolm I believe it was in Dead Beat, Malcolm says pretty much the same thing, but wouldn't elaborate on what he meant.  No, it was a pre-planned pregnancy and Malcolm was very much in on the pre-planning.

  I also think the whole point is that Margaret didn't go along with the Council's plan to create their own starborn weapon until she met Malcolm.  This was her way of foiling their plans, Harry just didn't inherit his goodness, he also inherited his independence. 

Was Malcolm a Scion of an Angel? Eb appears to have seen him under the sight.That is a weird description, like something you would say about a saint.  Malcolm is also the only character that speaks to Harry from the afterlife.

I've often thought that, or more in the line of Sir Galahad, the purest and noblest knight of the round table.

If it was Namshiel, if it is, Mab would REALLY want that coin giving Marcone something significant to bargain with.

What on earth would Mab have to offer Marcone?  He now has a fallen angel at his back, a wizard to boot, Marcone is about power, all about power.. 

A single Denarian is no match for Mab even Marcone/Namshiel especially now Mab knows, and Marcone would rather negotiate, especially if it gets him the power and immortality he wants without ties to Namshiel or Mab.

I disagree, of Mab could easily have taken on one of the Fallen, she would have taken out Andriel.  She didn't, instead she went for an elaborate plan to diminish Nic, but not kill him, thus releasing the coin to go to someone else. 

It really doesn't matter who knows as long as Mab does.  And she can't do anything about it since, as far as I know, the coins can't be destroyed. So keep your friends close, but keep your enemies closer. But you can be sure that Uriel knows.

Oh but when it comes to revenge, Mab has her ways, as Nic found out.  She might not be able to directly affect Namshiel, but she can make Marcone pay big time for taking up the coin.

“Prove it,” I said. “Sir Baron.” Marcone eyed me. Then glanced past me to the Queen of Air and Darkness. Mab’s eyebrow went up so far that it threatened the line of her skull. Then she said, as if to Marcone, “Much is explained.”

Butcher, Jim. Battle Ground (Dresden Files) (p. 385). Penguin Publishing Group. Kindle Edition.

Oh cleverly written, on one hand a flashing neon sign, "MAB KNOWS!"  On the other hand vague enough to give Jim wiggle room down the line.

Probably everyone in the room.

Harry is about as subtle as a bull in a China shop even when trying- and I doubt he was trying that hard since, y'know, fuck Marcone.

Not quite, if Harry wanted to advertise, he would have, with no subtlety.. I imagine Vadderung knows, the Archive/Ivy, but I doubt the others in the room know.  It is also possible that Molly knows because of her closeness to Harry, Mab, and because she is her father's daughter.

Remember Nicky was owed a favour by Mab before and during Proven Guilty, so wouldn’t the attack by the Denarians have erased that? It confirmed Nicky wasn’t in control of all the Denarians to Mab, as the favour still stood until Skin Game. Harry further confirmed this in Battle Ground with Namshiel.

Mab has a bone to pick with Namshiel for using Hell Fire on Arctis Tor, she states it clearly in Small Favor.  Wonder how she is going to react to Marcone once she finds out he has the coin.