Okay so 2 adults and 6 kiddos - That's 8 right -
Here's my suggestion, I would book 2 rooms, with the adjoining door in-between rooms, on the inside not rooms next to each other. BE very clear when making reservation's, This way you have access to everyone. You will 4 have double or queen beds, and 2 bathrooms, 2 TV's etc...
I would suggest a moderate resort -
POR or POFQ - this way you basically have use of 2 resorts, 2 food courts, 2 feature pools. Boat transportation to DTD, really nice ride. I think that POFQ and POR have the best food court.
CBR - This is a large resort, but I think has the best feature pool, has a cool little island to check out to. Who doesn't love pirates
CSR - We have stayed here, and this is a convention hotel, and has that feel, and just does not have that Disney feel.
On the dinning plan- I am a huge advocate of the DDP - I suggest DDXDP for this trip, This way you get 3 meals and 2 snacks a day plus a refillable mug pp ( the mug can only be used at resorts). With Counter service meals, entrée, drink and dessert included, for table service you will get appetizer, entrée, dessert and drink. If there are teenagers you will need this, my DD's could eat you out of house and home at this age.
We always go with the DDXDP - DH likes knowing that everything is paid for up front, except for tips, adult beverages, and souvenir's. This way everyone can order what they want.
As a suggestion head over to allears.net, and check out the menus with prices. They update them often.( monthly)
On a personal note -I commend you and your wife for wanting to do something nice for you nephews and niece. You can't believe what a difference this trip will make to them. You are showing them what family is really about.
Have a magical time.