What fun!!!
Here's my stream-of-consciousness reply:
Where are you staying? Are you on the meal plan? Either way, do you have some Advanced Dining Reservations lined up? I would imagine your son would LOVE Chef Mickey's
According to everything I've read (and I've read LOTS!!) one of the keys to a good trip with kids is to plan to get back to the resort each afternoon. (That's why I asked where you're staying; on site or at least nearby makes this so much easier!!) Those of us with young kids know that a hot tired child is a meltdown waiting to happen. So we, at least, are planning to get back for a swim &/or nap each afternoon. What it costs us in touring time it's bound to give back in sanity.
Also, be aware that stroller rental prices recently went way up. Take a look at the new numbers before you decide whether or not to bring your double stroller (or a pair of singles.)
One thing we're most definitely doing is having a grocery order sent to our room from either
www.gardengrocer.com or
www.wegoshop.com . Even with the meal plan, it will make things run so much better if the kids can have some cereal or a piece of fruit or a bagel before we start our day. (And it saves our meal plan credits for the more expensive dinners.) You can probably have formula, milk, maybe even diapers delivered-- a Godsend if you're flying.
We're bringing earplugs for my 5 year old; she isn't a fan of loud noises and it may make the fireworks and other attractions a bit more bearable for her. If it doesn't work, we'll just double team the kids; I'll head back to the resort wtih her (and maybe watch from the beach, where they're not as loud??) and my husband will keep the older 2 kids at the park. Worst case scenario, each of us misses some stuff. Life will go on and the kids will remember the vacation fondly, not as something they managed to get through. The same goes with Fantasmic and anything else we're not sure they'll love.
Another key to a good trip seems to be getting into the parks at opening. According to all sources, that first hour or so is golden-- prime time to see and do and experience-- before the crowds show up.
I've also been warned to build in at least one day of NOT getting up early. On our 3rd day (of 7), our plan is to hang around the pool all morning, then head off to Disney Downtown for some shopping before heading to Epcot for dinner and touring. Again, knowing my kids-- they'll need a down day by day 3.
Hope that helps a bit.