Kelly is with Blue team and the rest of (saber?) team in the shield world. Grey Team was said to be deep in covenant space blowing -blam!- up. Hopefully they wouldn't still be causing problems for the elites as that isn't good for Human-Sangheili relations. As for the halo wars spartans they are on the Spirit of Fire slowing making their way back to a UNSC controlled colony. Obviously due to the legendary ending something has happened.