As long as I was a CP, for some reason I ALWAYS had to sit on Main street to catch both the 3 o clock and Spectro parades. If I stuck around to see them, that is. My brother and I had no line for Pirates cause we caught it during the parade!
IllumiNations at Epcot: The best seats are probably right at the “front”; The area in front of the lake, directly between World Showcase and FutureWorld, where most everyone crowds. Last time I saw it, we found some seats off to the side, somewhere close to Mexico, Norway and China, and we saw it just fine. There are some benches there as well.
The trick with parades and nighttime shows is to GET THERE EARLY. Always gauge the crowds according to season. Skimp on dinner occasionally; grab some chicken and fries on your way to Fantasmic and eat it in the ampitheatre if they’ll let you, or take some fast food over to where you’ll watch Spectro, etc. My family must think I’m crazy, because I make them get to Fantasmic almost an hour ahead of time!