I wonder if this will be along the lines of that Pirates of the Caribbean "water adventure park" that concept art leaked out for a few years ago. Lazy rivers with elaborate show scenes that include animatronics and the like.
Depending on their long-term expansion plans, Universal would be wise to build a monorail/peoplemover to connect their properties. Overall, they're hitting home runs with all of the new facilities and attractions they've been building, but they really need to streamline the guest experience if they want to really want to get some good word of mouth out there. A fun, convenient transportation option generally makes a big, positive impression on people. Imagine a peoplemover styled after the iconic backlot trams from the studio tour in Hollywood, for example. But to have folks park in a huge garage, take two or three sets of moving walkways, track down a certain spot in a rather frenetic bus loop and then bus in to the park, that's going to leave a lot of visitors less than thrilled. You might argue that it's just as complicated to get to the Magic Kingdom, but there's some excitement associated with that in riding the monorail or ferryboat.
Wet 'n Wild regularly stays open until at least 8 or 9 every day over the summer, oftentimes even 10, so I imagine that would be easy to manage for Volcano Bay. Especially with three large hotels within walking distance.