Where is the FPP section for the Fantasy Parade? How early do we need to arrive with FPP? How long is the parade?
The section is right in front of the castle, on the center hub side of the street. There is no shade, so in the hot months, it's HOT. I'd arrive about 30-45 minutes prior to the parade if you want a spot near the ropes. It's about 20 minutes long.
Is it worth using a FPP for the parade?
Worth is subjective, as Keli noted, you need to get there early for the best places, so it doesn't really save that much time, but you do get the chance for really good pictures with the castle in the background.
We will be there the week after Christmas - does that increase the "worth it" factor because of crowds? I have FPP for all the parades right now.
It still depends. With those crowds, are there other attractions that would be a better use for you? 7dmt? That would be something to consider. If the parade is a major must do, then it could be worth it for you. You'll get some great pics too.
When are you going? Just read on wdwmagic that there will be two FPP locations for the parades during nov 29-dec 2. Check your MDE if you're going during that time.