Hi there,
I applied to Gatech Emory program as well. I received an email notifying recruitment event back in late Jan. The recruitment visit was March 4-6 ish. If you didn't get the recruitment invite, I think they might have already rejected you. Sorry.
In response to your question, 1). No I don't think you should email him, for he might not know what the whole admission picture either. I would email the department coordinator. 2). I think so. Plus the committee has the final decision when it comes to admission, so even if your PI stands up for you, there is still a good chance that most committee members don't concur and has to reject you. I know this sucks, but there is literally nothing we could do about that.
Hope this helps.