Sorry to be off topic, The planet in the H3 ending was most likely a Forerunner planet or possibly a Sang-heli colony(they are so fanatical as to be called Zealots, possibly fanatical enough to burn holy symbols into thier own planets).
I personally believe that Jorge warped with whatever part of the covenant cruiser to a location close to the Spirit of Fire, which also happens to cross paths with MC and Cortana a few short months later.
So if you put both of these theories together you get a co-op FPS with MC and Jorge working with the Elites against Brute retaliation for the Elites perceived betrayal of the Covenant.