The Shubert used to house the occasional play, but I don't think one has played that theatre since The Constant Wife in 1975. With 1,400 seats and two balconies, it's a little inhospitable for a play. Since Blithe Spirit is gathering a high profile cast and the show is slated for a Shubert-owned house, I would expect that they'll be in one of the prime 45th Street playhouses. All My Sons is slated to end January 11, and Blithe Spirit is to start in February, so the Schoenfeld makes sense... or perhaps they are waiting for the similarly-sized Jacobs, should 13 not make it.
Begin at the beginning and go on till you come to the end: then stop.