Really, how much "diverse alien culture" can be depicted in San Francisco? I don't buy it. Are you suggesting there is a "Little Andoria" near the "Vulcan Compound" and around the corner from "Tellaritetown" that the various cadets can visit for a taste of home?
Why not? The president of Earth, Jaresh-Inyo, is an alien, and so was his predecessor. Obama put a basketball court in the White house, Jaresh-Inyo could install a Grazerite park nearby.