Sun. should be a moderate crowd level. Mon. and Tues. will be low crowd level. Wed. the crowds will start to build and Thurs. should be surprisingly light crowd.
You are leaving just in time, because Fri. through Sun. will be slammed. Mon. and Tues. will be great days to be in the parks.
All that said, with your express passes, your waits will be minimal for most of your stay.