Overall, i try not to be too critical of others plans unless it's someone that's never been before, which is not the case for you, so I'll just make a few comments about specific things.
We LOVE Tusker House Lunch/Dinner Buffet, so that's my vote. However, it really depends on personal taste. The buffet menu is very Indian/African/Asian ethnic influenced, so if you are NOT adventurous eaters I would say you should probably stick with breakfast. Don't get me wrong, there's enough standard stuff for the kids, but most bad reviews I've read are mostly about how there wasn't things that people liked. As I said, we love it. (We also LOVED Sanaa - but same thing - VERY Indian.)
50's Prime Time is similar in the "antics" department. It's a lot of fun, and the foods good and not real expensive.
Interesting on the Via Napoli GC - I may have to give this a try...we are also going there on our trip. I'll let you know if it works.
With you on the Wishes Desert Party. We wouldn't have done it at the lower price, but at $50 a head, forget it. It's not like it's THAT hard to get a spot.
You talk about doing the Deluxe DDP - myself I say don't do it. To me, if you spend two meals a day in a sit-down restaurant, you are eating up too much of your day not enjoying the parks resorts. Plus it's just TOO much food. You can never get to ALL the restaurants you want to try any trip anyways. Pick one for each day, and then save the rest for the next trip. It's not like you're never going again, right?
And yes, 180 days out starts at 6 AM Eastern. Sorry for you...