Perhaps $10 admission and then sell tickets per ride. Thus will result in people staying for short periods of time which will allow a greater number of total visitors as people rotate in and out.
They can use the pay per ride quick queue system on the app so ticket sales could be contactless. And all rides could be reservation only, so they can avoid having the many people in the queue.
With only 1000 people and a fee per ride set up, getting a reservation for a ride won't be a problem.
Passes and memberships should be on hold like the park isn't even open at all.
Fun cards should be valid for 2021.
Edited to add: Italy, not France. More rides, restaurant, large shaded seating area that's easy to set up social distance tables, and they need to attract families - which means family rides. Also, on a hot day, Pompeii > griffin.