Here's the supposed fake leak:
"The guardians are old flood defense mechanisms. Chief is activating them so that Cortana in the domain can use them, cuz it turns out a fully corrupted Didact is leading the flood against the galaxy. ONI wants to use them to wipe out the rest of the elites while they're at their weakest, but Osman gets kilt by Chief and Halsey. Locke takes over ONI.
Not bad, if true.
The "osiris must stop the guardians" of the last level could be read as "stop the guardians from blowing the F out of the sangheili because Osman.
The "difficult choice" chief faces could be choosing between listening to Cortana or Osman, having to terminate the other, naturally."
Hmm... Yeah not bad, but the other seems to match more directly with what we already know as fact.
Also it seems like overkill when the UNSC could just park Infinity over Sanghelios and go to work