I'd 100% use it for PP. Even at RD, the line gets long fast. And with a toddler, it's not like you'll probably be at the front of the line. If you happen to sleep in or get delayed, you'll be in a long line.
My DD (who is 2) was obsessed with PP. Definitely one of her favorite rides. Even if she'd done it at RD, she would have been so happy to have the FP to ide it a second time later in the day.
You can see the parade from so many places, that I'd have a hard time justifying the use of the FP for that over PP. We got to the parade shortly before it started and had no issue finding a spot.