i have theorys on the BoBs. I might be over analyizing but here it is anyways.
Earlier in the post in noticed the halo reach planet is what is spelled from the missing letters in the data pad. I realized it was a website. I searched it and open it. i noticed it was for easter eggs and data pads. So here are my theories:
1. Maybe haloreachplanet.net is owned by bungie, 343, or someone important in the game, will post on their where to get the BoB helmet.
2. Maybe a way to get the BoB helmet is to:
Beat co-p campaign on legendary, without rest, killing at least one or all BoBs in all levels, get every data pad, discovering every possible easter egg, not including the ones that don't allow completion of level, and surviving at set time on Lone Wolf.
3. Same as 2 but true LASO (with blind)
4. Bungie's favorite number is 7, maybe it had do with the BoBs, kill 7 BoBs, kill the 7th BoB that can appear in all campaign levels, kill every other 7th BoB, etc.
5. BoBs orginated from Marathon, maybe (this might sound silly but) Bungie released a hidden update in the arcade version of Marathon since the release of Reach. The easter egg will hints towards the BoB helmet.
I know they sound extremely unlikely but maybe they could mean something, or im just over anaylizing.