Regarding the Expo, i have researched a little into the 'crowd level' theories somewhat as i too was curious.
From what i gather, most of the feedback i have heard other fans mention is that the D23 Expo does not influence crowds all that much in the Parks.
I found that surprising, but i have read this many times over the 3/4 months i have been researching a upcoming visit to my first D23 Expo.
What i learned from fan reviews was the crowds tended to be AFTER the Expo...as in, most show up that weekend to attend the Event and then stay the week after to visit the Parks.
So it would seem the week before the Expo would be quieter.
Take it for what it's worth....
I am assuming the first two weeks in August will be busy as the Summer season wraps up.