Hire Marty O’Donnell for music.
To be fair to all involved, Halo music has been excellent across all the releases. From the beginning of the post-Bungie era, Halo 4 has an excellent score, some of the best music in the series, imo. Not to denigrate Marty's beloved themes and scores, when I say that, of course. Despite barely working (afaik) for the last ten years, it says a lot that he's still being brought up.
Also, given that he's running for Congress, I suspect he'll have little time for anything else.