First of all, I'm very excited for all of you who get to stay there soon. I was at POP in January, and even then you could sense the excitement.
As far as a split stay and FD, here's my opinion. I've never tried, but will probably do so on our next trip.
We had the QSDP last trip. Even then, OMG so much food. (We brought cereal, bread, pb, granola bars... for quick in-room breakfasts.) There were times where I could have easily split a meal with someone. But because I was on a meal plan I just ordered my own.
So here's what I would do. My thinking is use the DP during the first reservation but eat what you're hungry for. Don't try to "use up" credits. Split a meal at Cosmic Rays or Pizzafari or Earl of Sandwich. Then on the last day of the first stay when you have your new room (with a refrigerator and microwave) go to the food court and stock up using the points you have left... Grab and go, fruit and veggies, stuff that reheats or packs easily...
If you are on the QSDP and want a TS meal or two, schedule those OOP during the 2nd half. (Or I suppose you could go the first half and save the QS credits.) Thinking the other way, if you upgrade to
DDP, get those expensive TS meals out of the way while you're on it. I'm sure I would have QS and snack credits left over if I was "loading up" on TS during the day.
On the second ressie, use a room-only discount if available. Use the food you picked up from the 1st ressie. Pack something when in the parks or, if you want a QS meal just pay OOP somewhere that's a good value. I'm guessing that would work out better than paying for another FD offer with a new set of tickets. This tactic may not work for everyone, but for me and the way my family eats I think it would be fine.
Be sure to take lots of pictures for us,please
Enjoy your time and I hope you will receive lots of 
WOWed!! I definitely would like to stay here one day. 
