I also think the numbers will be inbetween. I think 12k, i.e. 7 hours for off-site guests at opening after EEMH may be pushing it after the first week or two so I used 6k as an example to demonstrate how it could work without having much of an impact on those entering the park at 9am. Essentially, anything over 5400 will carry over to off-site guests.I think the numbers will be somewhere in-between. Your assessment would be for a 'normal' operating day, or for Toy Story Land. I don't know any 65 year old men who dreamed of riding a slinky coaster the way they dreamt about piloting the falcon back in the 70's. How many people would 6am EMH at AK attract for Flight of Passage today? The lines for the original WWoHP openings were likely, so opening early allows those that would have gotten into the end of the line at 7 or 8 are now getting into the park. They might see the line to get into the land, and then enjoy the rest of the park, or retreat to another park. It's going to be very crowded. Likely you've had people move their trips into the summer who wanted to avoid SWGE's opening, and those replacing them are those going for the SWGE opening.
You'll need 5400 people in line to make a 3hr wait, and I think it will very easily get to that. I also think that there will be people coming into the park and land during EEMH and the queue will build from there. Flight of Passage rockets to 180 min waits every morning, and Smuggler's Run will easily do that for a while I understand the huge difference with and without FP+, but it's still people's willingness to tolerate that time. I actually like the FoP queue, and 2hrs is 'not that bad'. I've never done that 2 hrs with my kids though. If the Smuggler's run queue is anything like Flight of Passage's, the 3 hr wait will be a lot more tolerable.
Early on, I might do a crazy early morning on my own, ride Smuggler's Run, wander BSO, and meet my family later either in another part of DHS or another park. When the crowds lessen, we'll do the whole land together and take our time.
As for the actual opening day(s) when it's a free for all at 6am, well then all bets are off. Should we do a "when will the first person line up?" bet? My money's on 2pm on the 28th of August.
Their tactic seems to be working btw: I've spotted multiple reports of off-site guests booking one-night stays in Disney resorts to get access at 6am for two days.