As mentioned above, the solicits mention Red Tornado getting torn a new one, yet again. I remember DiDio or Meltzer commenting on how we'll see a twist on the Red Tornado this year, so I'm guessing this storyline will provide the genesis for that.
I'm guessing the GL is Hal. If it was Guy we'd see the bowlcut outline
This is just my reasoning, although they could easily ignore it:
Guy's part of the Elite Corps thing, and is currently not stationed on Earth. Him making trips home to be in the Justice League just doesn't seem to gel, especially with people like Batman and Wonder Woman, whom he simply cannot get along with.
Could be John Stewart, but simply the hair outline looks to not support that. Plus people just don't seem to like him. I like him, but whatever.
Kyle currently does not have a ring and is imbued with the Ion power, his series will still be running by the time JLA gets off the ground, and I don't think they'd pre-empt the continuity for it. I could be wrong.
Which leaves Hal, unless they come up with a new Green Lantern, or Alan Scott ditches the cape and pulls triple duty in JLA, JSA and Checkmate.
Generic Flying Outline Guy: I like the sound of Captain Atom. Doubt it's a Marvel because of cape paraphenalia which would be outlined. Could be Booster, deepending on if they want to try and juggle 52 and OYL, making sure to reveal enough to tantalize without giving away any crucial story points.
As to the Mystery Woman: I'd like to see Vixen, she's definatley interesting. But check out her outline, seems to have bulky gloves and affects, I've always figured Vixen as a bit more streamlined, though that's a minor complaint and just me being nitpicky.
The Archer: Nothing to support it really, but I'd rather see Connor in the role. I'd like to find out where Roy is, he should be in Checkmate, I think.
Thanagarian: I'm guessing Hawkgirl, since she became popular with the cartoons and is currently staring in her own book. Although it could be the big OYL reveal for Carter Hall, so who knows. I think there's a logical point to each.
Edit: I liked Donnas WW costume, but whatever. Cape did seem a bit superfluous, I'll give you that much. I did like that they eliminated the U.S. flag motiff, as a Greek immortal godling-clay-mystical mirror image duplicate thing shouldn't be draped in a 200 year old country's flag.
Ninja Girl/Echo/Ronin mentioned in her last appearance she'd be keeping dibs on Silver Samurai and criminal activity in Japan, I believe. Sil lost a hand. Show's how well she's been keeping an eye on him.
The Collective was shit.
