It's worth noting that this is just a starting point for WDW. I am confident that when they reopen, we'll see additional health and safety measures well beyond what's listed here, but this is a good starting point. I think some of what they end up doing will be a bit more controversial for some guests (no character greetings, no parades/fireworks, temperature checks for guests, face masks for guests).
I don't think we'll see MK operating at 75% capacity for quite some time. I don't think MK will open at even 50% capacity (45K guests). These seem to be baselines for all parks. Keep in mind, there are many days of the year when MK doesn't normally operate at 75% capacity. MK's capacity is just below 90,000 guests (so high 80s), so 75% of that would be about 67K guests. That's generally the amount of guests MK expects on Memorial Day, for example. The "average" occupancy for the park is around 55K guests. If they're going to be reducing actual capacity of attractions and then further reducing them by interrupting operations for cleaning (and still wanting to avoid bottlenecks and over-crowded public spaces), they'll have to limit capacity to somewhere between 20k to 30k guests (i.e. a
MVMCP or
MNSSHP) , and initially, it might be even lower. Touring Plans did a calculation to see what the capacity would need to be for everyone to get 6 square feet. The official acreage they used included backstage areas but they argued that the factor of members of the same household not needing to social distance cancels this out. Not necessarily endorsing this estimate, but they came up with an initial reopening capacity estimate for MK of about 15k to 20k guests.
In addition to what you talked about resorts (I put up a detailed post on the N&R forum with different resort occupancy scenarios) , I could easily see WDW asking APholders to "reserve" their spot in the park similar to what
Disneyland does with their FlexPass APs. This way they can cap how many people are showing up to be in the park.