My heartfelt advice would be to take in the parade on the day in the park when you have the energy to be there, the weather is good, the kids are still doing all right.... Life at WDW, especially when traveling with young children, is so much better when you can be flexible and have a broad plan (we'll aim to see one parade!) rather than rigid (we HAVE to see the MK parade! Today!). All the parades have their own charms, and I honestly think you'd be happiest seeing the one on the day that you have the energy to see it. One aspect of parades that "can" be tough for little ones: in order to see and sit down, you'll want to scope a spot out a bit ahead, so that involves some waiting for the parade to start, and that can be difficult and boring. So really, all the more reason to see when/where/if opportunity strikes and go with the flow. Have a great trip!