As you said Quantus "in many places back in SK, Sidhe and Fae are used completely interchangeably, without any distinction of type /or/ status". The most probable explanation here is that Jim changed his mind later on in the series (SK was pretty early after all).
I don't get why them being beautiful contradicts them beings like Cat Sith being among them. Cat Sith is probably pretty hot...if you're a malk
.
My interpretation is that the Sidhe are exemplars and rulers of their particular Fae type, so there's only one Sidhe of each type. Looking back on the quotes this seems less likely.
I think that Mab and Lea are Sidhe Little Folk. This fits with this WoJ:
Q: How big will Toot get?
A: Depends on how much influence he has in the world. That’s how the sidhe gain their size and power. Mab wasn’t always as big as she is now.
Mab was also (to my knowledge) first mentioned in
Romeo and Juliet in the speech by Mercutio. He says she's "In shape no bigger than an agate-stone" (The full speech:
"O, then, I see Queen Mab hath been with you.
She is the fairies’ midwife, and she comes
In shape no bigger than an agate-stone
On the fore-finger of an alderman,
Drawn with a team of little atomies
Athwart men's noses as they lies asleep;
Her wagon-spokes made of long spinners’ legs,
The cover of the wings of grasshoppers,
The traces of the smallest spider's web,
The collars of the moonshine's wat'ry beams,
Her whip of cricket's bone; the lash of film;
Her waggoner a small grey-coated gnat,
Not half so big as a round little worm
Pricked from the lazy finger of a maid:
Her chariot is an empty hazelnut
Made by the joiner squirrel or old grub,
Time out o’ mind the fairies’ coachmakers.
And in this state she gallops night by night
Through lovers’ brains, and then they dream of love;
O’er courtiers’ knees, that dream on court'sies straight,
O’er lawyers’ fingers, who straight dream on fees,
O’er ladies' lips, who straight on kisses dream,
Which oft the angry Mab with blisters plagues,
Because their breaths with sweetmeats tainted are:
Sometime she gallops o’er a courtier's nose,
And then dreams he of smelling out a suit;
And sometime comes she with a tithe-pig's tail
Tickling a parson's nose as a’ lies asleep,
Then dreams, he of another benefice:
Sometime she driveth o’er a soldier's neck,
And then dreams he of cutting foreign throats,
Of breaches, ambuscadoes, Spanish blades,
Of healths five-fathom deep; and then anon
Drums in his ear, at which he starts and wakes,
And being thus frighted swears a prayer or two
And sleeps again. This is that very Mab
That plaits the manes of horses in the night,
And bakes the elflocks in foul sluttish hairs,
Which once untangled, much misfortune bodes:
This is the hag, when maids lie on their backs,
That presses them and learns them first to bear,
Making them women of good carriage:
This is she—"
Although Mab is supposed to have been the only Winter Queen and the Fae are supposed to be ancient so...
Also, here is another WoJ that plainly states that Little Folk can become Sidhe:
With all the things Toot Toot and the Za Lord's guard have done that made a difference, and with Toot getting bigger, is that going to upset the balance in the Summer court?
The answer is no, because they are not Summer anyway, they are wildfae. And everybody over in summer is going to blame Harry for everything they do. They regard them as a tool and Harry is the guy holding it. Harry would tell you that he's probably the tool but... Anyway Toot Toot's been growing because that's where the Sidhe came from to begin with. They weren't always all tall and glamorous, they kind of got that way.
EDIT: In Cold Days
Mab says she was mortal once. This can be explained by my theory that the Little Folk are changelings who Chose when they were children (Justification:
Doesn't it seem wierd that we never see Fae who look like children? It's true that we may not have seen them but it doesn't really seem in "theme" with the Fae for that to happen (IMO). This also explains how Mab could have been mortal once and "not have been as big as she is now".
