I've enjoyed reading along with your pre-trip report! You've done so much research and planning (too much for most people!) but I can tell you enjoy it! I hope your family appreciates all of that work (and fun work) that went in to planning and prepping! And, I learned a few things reading through your plans too!
I leave on Sunday 5/26, so our times overlap a little. One thing that I was not anticipating (and maybe was a wild card for your plans too) - THIS HEAT. It is markedly going to be changing up some of my pre-planned ideas, and I am prepared to also adjust on the fly when we are there because that heat is going to zap us. I have ALL the cooling items as I'm sure you do too, and planned breaks during the hottest times. I'm sure you are considering that too. With the little ones, it might be a good idea to prepare for a bit extra on the pool and nap time, and maybe even a swim suit into the parks for things like a splash pad in Epcot or MK. It's nice that you have a good amount of ADRs to sit and relax in the cool climate!
Enjoy your trip! Everyone will get feeling better soon I hope and you'll have a great time!