Starting early and staying till 7pm with express passes should let you get pretty much everything you want done, with the exception of the Hagrid ride.
The only rides available during the extra hour are Minion Mayhem and Escape from Gringotts. You have to pass Minion Mayhem to get to Diagon Alley, so it makes sense to do that one first and then head round to Diagon Alley and do Escape from Gringotts. If you're still in the extra hour then you could spend the time until regular park opening looking around Diagon Alley.
I assume you have a park-to-park ticket, so have a look at the rides that are available and prioritise them. If more of your top priority ones are at Islands of Adventure then head over there and work your way round the park in a circle. Shooting back and forth makes everything take longer. The way we usually do IoA is get off the Hogwarts Express, head through Hogsmeade to HP&tFJ, and then continue in an anti-clockwise loop of the park.
The wrinkle for you is the water rides at Ripsaw Falls & Bilge-rat Barges. You WILL get wet on these. We usually leave these until the end and do them just before heading back to the hotel. If you do them early then you'll be in wet shoes all day (never nice) & if you do them late you've no hotel room to return to, so you'll be wet heading on to wherever you're going.
If most of your top-priority rides are in Universal Studios Florida, then the same principle applies. Try and figure out a route that involves as little backtracking on yourself as possible.
The big thing is to not stress about maybe not seeing/doing something. Enjoy your time there together, and if there's something you really like, maybe do it a second time while you're there, as that'll be easier than trying to come back to it later.