We did this one year between a value and a deluxe (Wilderness Lodge). I have got to say I didn't care for moving in the middle of our trip. It was disruptive to the trip and a huge pain. It was also the only way I was willing to pay the deluxe prices, 2 days as opposed to the entire 10 days we were at WDW. We do have little kids (too little to help move) with a lot of stuff so that could be part of the problem. If your children are old enough to help carry the stuff, it might be easier. For us, we don't plan on doing that again.
I'm not sure about ME, but I think you can arrive at one resort and depart from another. We had a rental car that trip. I think you have to make two separate reservations. I would probably just do free dining where you will stay the longest and pay OOP at the other hotel so you don't have to pay extra for tickets. I would just get the number of days you need on the tickets associated with free dining. As I am sure you are aware, tickets are cheaper the longer you stay. I would also get tickets for the days you are at Beach Club. You are so close to Epcot. You could just pop in for a couple of rides (think FP+ rides) and dinner, which would still leave lots of time for the pool.