Hello-
I'm here now with my family and we just did both Fantasmic and the Frozen fireworks show on the same night. We did the Frozen fireworks show at 9:45pm and then Fantasmic at 10:30pm. I am assuming that you could do it the way you're thinking of....9:00pm Fantasmic and Frozen after. It's a cool show.....every elementary-aged school girl in the park was in their glory! Enjoy!