Live albums were traditionally cut down for length; most people don't seem to have a problem with Bullet in a Bible's presentation. But most will agree that we want all the songs, even if the chatter and looped parts are cut. I'd rarely listen to those extended live tracks at home, but somehow it makes road trips go faster.
21CB is VERY likely. That album probably wasn't far behind Dookie and American Idiot in terms of popularity. If Warning can get this kind of love, there's no telling what else is on the table. The Lookout albums would be cool, but there's just not as much in the vault. I know they have decent soundboard recordings for each era, so if it's only an album/live album combo, I'd be a happy camper. If they manage to find even one unreleased studio track, I'm preordering immediately.
As of late, I'd believe it. Too many silly mistakes and shortcuts slipping through the cracks. If they could use the wrong master of American Idiot for an American Idiot release, then anything's possible. The issue of withholding tracks has also made me a bit jaded; the BBC Sessions remove two tracks from the sessions, and the deluxe version of Saviors still kept a Japanese bonus track off the album.