Can't help you with the meals, because we stay offsite and bring our own food in.
If it's your first trip to WDW, that's awesome!!! The first thing I'd suggest is that since you'll have 14 days, don't try to cram everything in during the first 7 days. I'm sure you'll be beyond excited and want to try to do everything, and I wouldn't blame you. But resist that temptation. WDW is bigger than you can imagine. Words don't do it justice. You will do more walking than you think. So if you try to rush and cram it all in, you'll crash and burn. I don't necessarily think you need to rest for hours each and every day. But at the same time, don't overdo it.
As for the water parks, we love them. We also are lucky enough to be able to take long trips (we have annual passes), and when we're there for 2 weeks, we hit each water park at least 2-3 times each. They're awesome. As for which one, I'd suggest checking WDW website to get more info on both, maybe look at some YouTube stuff, and decide from there. They have a lot of similarities, but some key differences. Both have lazy rivers, tube slides, kiddie areas and wave pools. But the wave pools are drastically different. The one at TL has waves like you've never seen. They are HUGE, and a ton of fun. The one at BB is small, frequent waves. April should be warm enough, especially during mid-day.
As for how many days in each theme park, that's really up to you. For most...myself included...MK is the "heart" of WDW. So I'd spend the most time there. If you're there 14 days, personally, I'd be in the parks each and every day (like I said earlier, not running around all day every day, but at least spend some time in a park). I'd plan at least 3 or 4 of the days at MK. I'd do 2 or 3 of them at HS, 3 at Epcot and 3 at AK, or something like that. I'd throw water parks and Disney Springs in as well, at least a few times. For example, maybe you'd have a day where you're in MK, but only from 9am to 1pm. Then go to the water park from 2pm to 5pm. Then go back to your hotel, have a relaxing dinner somewhere, or something like that. If you want a night out, you can do the opposite. Chill at the hotel in the morning, maybe go to Disney Springs early afternoon, then hit the parks from 3pm to close.