We took my parents for their first ever trip to WDW in October. We had such a good time and I know your family will too! Here were their favorites:
Chef Mickey's. We did dinner, they really enjoyed the selections and seeing the characters interract with our kids. They also enjoyed seeing the monorail move through the building and twirling their napkins.
1900 Park Fare. We did breakfast, it was wonderful. The charm of the Grand Floridian really appealed to them and the food was wonderful. Probably the best breakfast buffet I have done at WDW or
Disneyland. It was perfect to eat there and then ride the monorail to TTC and then on to Epcot which my dad really enjoyed.
CRT. We had dinner there before
MNSSHP and it was wonderful. I think you mentioned this one already, it is just magical to eat in the castle.
Sci Fi: I think this might have been their favorite believe it or not. They just loved eating in the car, the burgers and the movie clips. They both died laughing remembering those funny movies they used to go and see! We did lunch, I like that menu better.
Kona Cafe. Really nice for lunch and they enjoyed it. But when DH and I had dinner at O'Hana in December just us, we both mentioned that we wished we would have brought my parents there too! We saw an extended family at the next table which just added to our missing the grandparents and knowing they would have loved the food and atmosphere.
Libert Tree Tavern. Again, they loved the characters, being right in MK and the food was nice, normal, all American food that appealed to their palettes.
Rainforest Cafe. They enjoyed this a lot, we had been to the one in Disneyland before so it wasn't a big surprise that they would enjoy this one.
They really enjoyed Columbia Harbor House for counter service as well as the hot dogs at Casey's. We also ate at the food court at ASSP's a few times before moving over to Saratoga. That was sort of a crowded nightmare but they had fun so I guess it was okay. After that when we did cs it was usually at Artist's Palette in Saratoga Springs. This was also duing Food and Wine Festival so that was nice for cs options.
In January, we took DH's parents to Califorina Grille and Le Cellier and they really enjoyed both of those. I know my parents would have loved Le Cellier (I wish we would have gone there instead of Marakkesh which they didn't like too much) but I don't think my parents would have liked Ca. Grille the way DH's family did. And I thought it was as noisy in there as Chef Mickey's! Dh's parents enjoyed Tusker House in AK, they have a pretty varied menu and we lucked out and saw some African muscians while we ate. I found my parents seemed to enjoy the more family friendly places because they enjoyed seeing the grandkids have so much fun. Also, my dad hates to wait so I made sure to make ADR's early or very late when it was less busy. Buffets were also good since he has diabetes and needs to eat pretty regularly and can't get too starved. I also recommend eating at the resorts which are almost attractions in themselves. They also usually have plenty of places to sit and wait for your table which was nice. I wish we could have explored the Epcot resorts. Dh's family enjoyed the AKL and Boma quite a bit and I think my parents would have too. You need a lot of time to get all that dining in!
Good luck and enjoy your planning!