In a bit of a change of pace from THQ's usual m.o recently, where THQ usually refuses to say yes or no on anything... People have been asking Cory and others if certain people are in the future DLC announcements, and they aren't saying who they are... they are confirming who it ISN'T.
Based on these conversations, we can rule out:
Ultimate Warrior, Chris Masters, Tyler Reks, Trent Beretta, and Curt Hawkins.
People have asked THQ if they are the remaining 14, THQ has stated they are not. There may be more to come.