Hi Ryan!
This sounds like a fantastic vacation! I love when we can get to Walt Disney World and stay for an entire week (or more). Anything less than that makes me feel rushed to get everything in that I want to do.
You don't have to have the Park Hopper option to visit a water park (or any of the other
& More places) on the same day you visit a theme park. I think the Water Park Fun & More option is great. Some days we will spend a half day at a park, and the other half at
DisneyQuest Indoor Interactive Theme Park at Downtown Disney. With two teenage boys, that is a must-do on each trip!
Just so you know, you can also use more than one of your "fun" visits on a single day. For example, if you wanted to visit a water park in the morning and then play miniature golf in the early afternoon, you can do that. Just keep in mind that the miniature golf has to be played (or at least started) prior to 4:00 p.m.
I hope this helps. Please let me know if you have any other questions and have a very magical vacation!