We've been twice with young children and found quickly that short trips into the parks worked best, not least because of the number of exhausted, frazzled families we saw who'd tried to do from park opening to closing fireworks. Also it felt like we had more of a traditional holiday at times - splashing round the kids water play areas, eating ice cream etc outside of the park environment (which we all love but could be quite intense for the kids, especially in the heat).
We found into a park at opening, three hours or so of rides with breaks for snacks (sharing a cinammon bun in Gaston's Tavern is a family highlight), back to the resort for siesta, swimming or down time and then out for dinner was the way forward - although ours were a lot younger so we did early dinners.
Really jealous you're staying at Animal Kingdom Lodge - Boma was one of the loveliest places we ate and great with kids cause it's such a broad buffet of unusual things.
Do you have the dining plan? If so try and book some really good stuff that takes advantage of it, you can eat world class food for the cost of tip. We love Narcoossees because we love lobster and seafood, the steak place at the Yacht and Beach Club is phenomenal too. Because of the dining plan we did we did a fair amount of character breakfasts - e.g. Tusker House in Animal Kingdom, Crystal Palace etc which means you can get into Magic Kingdom early. In part it was because the meals were effectively free (bar tip) but if you get an early reservation you can get into parks early which worked for us. Also, the first time the kids met the characters they were a bit freaked out, by the end DD was bellowing 'hey Goof!' across the restaurant because of course Goofy was her friend and just making small talk with these other folk before he got to her.
What kind of food do your kids like? And what characters?
Ohana in the Polynesian is good food but amazing atmosphere - also they do a dancing competition type thing for children which our DD loved and which meant dinner lasted a bit longer than it might have otherwise. We ate a lot of buffets too, really worked well and minimised waiting, although to be honest barring the really posh signature dining the meals come out really fast in American style.
You're going to have a fab time!