Isn't there only room for one new lounge in Concourse B (which would presumably be an Admirals Club)? If The Club was going away this whole time were they planning to go away for good?
No, the two lounges will be right at the entrance of Concourse B, upstairs from basically where the food court is now. One will be The Club, the other will be a relocated and expanded Delta SkyClub (JAA has confirmed both of them). Space-wise, it's basically at the confluence of all three concourses so easy access to all three.
AA nor JAA has announced an Admiral's Club. Remember, while they're going to take 5 gates, it's a net increase of 1 (they have 4 now).