Summer is busy and hot, so cannot get around either of those.

The heat and humidity can be oppressive (no exageration), so if possible, choose a resort where you can easily go back during the hottest part of the day and relax.
We've been all of the times you mentioned. The time we went a few days prior to July 4th it was pretty low key until July 3rd, then the lines were hours long! Late June would include just before the first week of July.
The 2nd week of August became our favorite summer time to visit. Festive, but not body to body guests. We do not do commando, but plan early mornings, return to room around noon, relax/swim or whatever (one day for DTD) until 4 to 6ish, then head back for the evening - we rarely stood in a line.
The heat can be horrible, but I still like that time of year. With
free dining beginning later in August, the first 2 weeks should be pretty good crowd wise

Crowded for sure, but not horrible.
My children were exactly that age on their first WDW visit

They are all grown up now and we are excited about the arrival of our first grandbaby this September!
Sounds like so much fun!! Have a wonderful time planning and a magical trip!
