Beast's just running the school (probably my favorite line in
Regenesis, by the way

). Think of it as his day job; he moonlights with the Secret Avengers, stopping underground problems before they spill out into the open and threaten the world (which, of course, makes him the most awesome principle/headmaster ever). The principle/headmaster can always take a day off and leave the day-to-day stuff to the rest of the staff.
I wonder if Storm is joining the Avengers to be around real heroes. Cyclops pretty much told her that she's going to be his only moral compass after the split, which is a lot of pressure. Maybe she joins the Avengers to get a dose of how proper heroes operate so she can then pass that onto Cyclops. Or maybe I'm giving this too much thought and she'll join just 'cause.