Many of your questions have been answered a month or so ago at Legions of Gotham. A quick recap:
so is she actually making it to MASS MARKET?
(and which version??)
Sort of. She'll be unmasked and available via Diamond.
and what up with that head? Yin isn't it?
That's the Unmasked Catwoman head.
Are we getting Alfred or Rojaz or a new Bruce? what about the Mayor? (V = Adam West!)
Not at this time. During LOG's chat with Mattel, we suggested a number of those figures with Alfred leading the pack with the most requests. It's been seen by Mattel, that's all we can do at this point.
Trenchcoat guy = Blockbuster? I thought I heard he was going to appear on the show.
Nope - not Blockbuster. More will be announced on that character soon.
Riddler - mass market or exclusive?
Both. He'll be available initially via Diamond, later via Target, WM, etc. Much like the Hawkgirl 10" figure was done.
and any chance the 4pak will swap out one of those Bats for someone else?
and is the Freeze in 4pak exclusive or single carded, too?
We're having a chat with Mattel after the con, so we'll get some more info on the 4 pack at that time. Freeze is going to be available single carded.