Hmm... So if Chief is AWOL, then maybe Blue Team is following him and not ONI/UNSC orders. One loose Spartan II is one thing, FOUR is a whole other ball game. How will they explain this to people not familiar with Blue Team? I don't ever remember seeing them in games, or even mentioned. Except for Linda in Halo CEA.
They were in the H2A terminals as well, the last one I believe. But that's still pretty minor in the grand scheme of things I suppose. They're need to do a good short and sweet introduction for the non-Lore fans for sure.
I could see it play out this way:
Locke & Co are heading into a confrontation or whatever, Locke could be going over Blue Teams specs & accomplishments to his other squad members, explaining to them (and the audience) some of the background. It wouldn't be too ham-fisted, and could be really cool.
The last we saw of them in Escalation they were taking missions right and left, but NOT AWOL. By HTT we know the rank & file are grumpy that Master Chief is off 'doing his own thing' and operating with a LOT of leeway but again it doesn't appear him or Blue Team are AWOL.
Obviously something has to happen in the lore to get them from point A to point B where Locke is after them, but we don't know what that is yet.
Overall question. Do we know if John has officially told anyone of the Librarian "restoring" the human genome in him?
Doubtful, he'd of have a debriefing after the events. I can't imagine ONI would let him be, but by TN72H he's back in action so it couldn't have been too long or too in depth.
I could see him telling Lord Hood maybe, but only if asked, he doesn't seem the type to volunteer up any information.