Ok, I'll throw in Fantasmic.
1. It's usually early.
2. SEATING.
Your 4 and 7 year old have the chance to simply be looking at other ppl's shoulders for a good portion of hea and SW unless you grab a good spot. Good spots can definitely be found, and HEA is great, but just know that going in, shorter viewers can be at a major disadvantage in the wrong spot.
Fantasmic is in a seated outdoor theater.
On this board, and others, there have been complaints of ome kids finding it to be scary, but it's Disneyworld scary. There's a fire breathing dragon, a wicked witch, and Disney scary music during the Disney scary scenes.