Until we start getting live reports back, check out this Parks Blog Posting. They outlined how they planned to distribute the FPs...hopefully it works well!
So I was there last night and when you get in line for the fastpasses, you can get fastpasses for both. It wasn't crowded in the am, you could just walk up and get the fp for both shows.
I've heard that if there is a line you have to go through the line twice to get the two different shows. When we went last week there was no line so you could get FP for one show, then step a few feet over and get FP for the other.