Oh I think it was more than that, for the simple reason we have on more than one occasion one Senior Council member saying to another with a wink and a nod about knowing what Harry was supposed to be.
Wizards -- especially wizards as strong as the Senior Council -- don't share well... especially they don't share their
secrets well. WoJ says they have all the pieces of the puzzle, but it's all split up in different hands and they
aren't sharing.
It's precisely
because of that wink-and-nod that I think they don't all know: you don't wink-and-nod that way unless there's multiple layers of meaning, insiders who know and outsiders who don't; or layers of meaning, with progressively more-or-less informed.
Maybe some of them think of Harry as a violent borderline-sociopath proto-warlock, "meant to be" DuMorne's merciless enforcer (this is, I think, the "Official Story" given to the rank-and-file). Maybe some of them think of Harry as "meant to be" a Destroyer (whatever that is, presumably an overpowered agent of chaos&destruction with some sort of fate/destiny thing pushing them on); this is the "secret" given out to some, who realize there
is some further secret. Maybe some of them think of Harry as "meant to be" a full-on Starborn, summoning & compelling Outsiders who outclass even White Council wizards; this is the kind of dangerous info that they don't give out -- you learn it when you figure it out for yourself.
Everyone winks and nods and moves on, but some are more-informed than others.
... For starters, how is it that so many know Harry was star born to begin with? Lot's of babies born world wide at the same time Harry was, but that doesn't make them all star born ...
I don't think we know; but I suspect that it's only wizards who can be Starborn; or at least, they're the most-meaningful ones. A muggle who's resistant to Outsiders still can't banish them or
or those other useful magical bits; just personally resist.
I think some of the older wizards have sufficient "starborn" info to figure out that Harry is (or may be) one. I presume Margaret gave birth to Harry in a semi-normal setting (doctor in attendance & birth-certificate & all that). So Margaret's son would be known to be born at the right time (once they knew to look for him). But "that son of a bitch" DuMorne somehow tracked him down first; and after a few years in Justin's hands, they couldn't be 100% certain what was hidden inside Harry.
... Oh I won't argue with you on that, I think it's been established that wizards live maybe 350 years give or take if all goes right, I wouldn't be shocked if Mab was closer to a thousand years old. The only possible exception in my mind would be Rashid. I think he has a thing going with the Mothers, they gave him his eye a very, very, long time ago, and his background is more complicated than you think that's why he is fit to guard the Gates.
Yeah, Rashid is much older. WoJ places Rashid as being a potent wizard around 735AD, taking down a powerful Outsider-summoning wizard (Jim explicitly takes from HPLovecraft's
Cthulhu Mythos; HPL's fiction was clued-in, like Stoker's
Dracula, though AFAIK we don't know who clued Lovecraft in, or why they did so).
I recently saw a theory that Rashid is one of the old Gods, like Odin. One thought he *was* Odin (just a different Mask) because of Rashid's eye-thing; another pointed out Rashid being maybe Egyptian, and could maybe be the god Horus, who looses one eye (but it's later restored to him). Also in the Egyptian pantheon, we have Anubis who's explicitly a gatekeeper (one of the god's formal titles). So... lots of potential links, there!
But there's a crapton of time-dilation to be had in the deep Nevernever -- where the Gatekeeer perforce
must go -- so Rashid could be legit mortal, but spends so much time in wonky 10:1 timeflow that his aging just doesn't match up with even other wizards.
... I don't argue with most of that either, Margaret also knew that, and knew how the White Council, maybe Mab, and or even Lord Raith wanted to use her as a brood mare for a star born babe. However Margaret turned the tables on all of them when she selected Malcolm to sire her star born babe.
I doubt she saw through Mab's machinations; that's tough to do! If she had -- and thought Mab was wrong -- then she'd hardly have picked Mab's Handmaiden to be Harry's FG! Since she was inside Raith's own household, though, I think it very likely she managed to find info that he (and/or his allies) didn't want her to have; and of course she was already suspicious of White Council shenanigans, and likely could have seen through some of that plotting (particularly given Rashid's testimony that he and Margaret sometimes met on a friendly basis, as fellow Waywalkers).