I expect soft opening for Pass Holders who can book a timeslot to come (down time possible of course). Then slowly park guests will have the possibility to book a timeslot of the same day (if the ride doesn't break down. Summer opening with televised ceremonie including actors from the movies and select guests.
Then the same protocol for Hagrids for everyone.
While this makes perfect sense from a safety and operations POV, it sounds a little too set in stone for a soft opening. However, I don't see any other option as you're going to have crowds of people hanging around JP waiting for a chance to ride.