I've never needed an FP for Philharmagic. Last trip, we saw it twice in a row with no wait. I don't think you'll have any problems when you are going.
One thing I will suggest...Fantasyland really seems to empty out around dinnertime (6pm and after) When we went in early May, FL was very crowded in the morning and early afternoon, but when we went back at 6:30, we walked on to Pooh, Philarmagic, Teacups and Small World and only waited 10 minutes for Dumbo and Peter Pan. Toontown was also much less crowded during that time.