Well, now I'm REALLY in. The assistant dean communicated with me as though I was, and then an administrator got in touch wih me two weeks ago to say, No, you aren't.
Today I got the letter from the 'true dean,' officially notifying me of acceptance. Hallelujah. It says that their decision to accept me "was based on the evidence that [I] have the qualifications to do graduate level work."
Now I just need to know what weeks I can take off school in the spring to go to New Zealand.