Per this thread on gaf this is happening.
Halo 2 Anniversary along with a whole bunch of other MS news. Keep in mind that the guy posting had to reveal via PMs to admins his sources, and the admins allowed it.
Halo 5 is apparently pushed to 2015, Halo 2 this year which makes sense given the new ilovebees activity such as Major Nelson's twitter post, etc.
Halo 2 Anniv rumored to have original online multiplayer with all the maps on xbox one.