Congrats on your first family vacation! We will be there the same week you are, the 22nd-29 for our DS's first trip
I am a seasoned business traveler, though haven't had much experience traveling with kids, but some things you mentioned are in my sphere of experience so:
1. Do not take any jewelry. It might get lost or stolen and really isn't necessary at WDW. Wear your wedding ring and watch, and medical alerts if needed and that's it. I don't even wear my diamond wedding ring when traveling, I wear a plain gold band.
2. Pack only the most basic cosmetics. Your moisterizer, foundation, one blush, one neutral eyeshadow, one neutral lipstick, one eyeliner pencil if you wear it and mascara. It will all fit in a tiny bag. Put one big tube of toothpaste and all toothbrushes in a Ziploc. I usually pack a full size shampoo and conditioner (not quite full though) also in a big Ziploc in case they spill. I also throw in a bag of disposable razors that both me and hubby can use
3. Get a note from the kids doctor that they have special needs and any special techniques that may be employed to take care of them. I know of a parent who had to produce such a letter when her son had a meltdown in a store and she was doing some kind of holding technique, as someone decided she was abusing the kid and called the police.
4. Pare down shoes to the barest minimum or they take up too much room. Comfortable walking shoes, cheap rubber flip flops or
crocs for the pool, and maybe one nice pair for a special dinner. Consider wearing the flip flops/Crocs to the airport, no matter how they look, as it will make it easier to get through security and take up less luggage space. Pack socks in the carry on for the flight in case someone's tootsies get cold.
5. Pack mix and match outfits and stick to two or three basic colors for yourself and hubby. I have found packing all khaki, black or navy, and white works well. That way you can wear the same khaki shorts a few days (as long as you don't get them stained or very dirty) with different tops or the same top with a pair of shorts, then later a pair of pants. If you have linen, pack it. It's the coolest fabric to wear in our climate, is expected to get wrinkled, and dries fast if you want to wash it out in the sink and hang it to dry in the shower. Also, in this climate, plain cotton undies are the most comfortable. Leave your pretty silk and satin and lace at home...trust me! If the whole family has plain white cotton, they can be washed in one load.
Best of luck and have a great time!