I wouldn't be surprised to see masking continue indoors. Disney is protective of their "family friendly" reputation and younger children won't be vaccinated until next year.
Certainly, if cases are under 500 per day nationwide by October, I could see all indoor masking gone everywhere. (Israel is now at 49 cases per day, less than 1 death per day, and they are continuing indoor masking). But I fear we may see mini spikes again by October. Nothing like October 2020, but mini spikes in locations with low vaccination rates. May be enough to continue indoor masking at places like WDW.