You have to either be an employee of Bungie or have completed all of the Vidmaster Challenges. And there is a myth that there is a "recon skull" apparently in Cortana. Or at least i think it is.
the recon helmet for halo 3 is unlocked by completing all of the vidmaster challenges in halo 3 and halo odst
you have to work for bungie to get recon
Halo 3 recon was never officially released it is thought though that it was the original name for Halo 3 ODST
no, Halo 3 Recon
i think its is going to be similar to halo 3
Its not the recon that you would get in normal halo 3, it's different, its more like mark VI than recon in halo 3.
Yes
you get all the vidmaster achievements on halo 3 and halo 3 odst
you have to get all vidmaster achievements to get recon.
recon armor
Recon Armor is only given out by the developers of Halo 3, Bungie. In the past, they have given out the Armor to the creator of "Master Chief Sucks at Halo," as well as the creator of the a video in which a player was killed by a traffic cone. One set of armor was auctioned off by Bungie as part of a package at the Penny Arcade Child's Play Charity Dinner. In any case, the only way to "get Recon" is for Bungie to give it to you.