So I just got done listening to the Rebel FM gaming podcast and one of the hosts who is also an editor for IGN (Arthur Gies) played Halo Anniversary recently, and while he didn’t give specifics he did say that people should stop complaining the multiplayer being just Reach’s MP until we see the game at PAX. So basically he all but confirmed there will be Halo:CE multiplayer in the game.
If you want to hear it yourself the episode is Episode 110 and he starts talking about Anniversary at about 37 minutes into the podcast.
P.S. Sorry if old.
EDIT: here’s a direct link: Rebel FM