1. Magic kingdom
2. Animal kingdom
3. Hollywood studios
4. Epcot
If the water parks are open when you go, then if put them at 3. My kids love water parks.
You don’t need park hopper. There’s plenty to do all day at each place.
With little kids, we’ve found going right at rope drop (can’t stress how much better your experience will be if you are there waiting before the park opens) until lunch time-ish is good. Then back to hotel for naps. Then head back later afternoon and party as late as the kids can hack it. The naps make all the difference.
Doing the character experience breakfasts or lunches at one of the Disney hotels are great.
If you’re going during holidays where you can do the Halloween or Christmas party, I’d seriously consider it. They’re fun and the park is less crowded, especially as it gets later.