You have several kids right around Disney's magical 'child v adult' dividing line. At a TS with a regular menu the "children" must order from the kiddie menu while the "adults" must order from the adult version, even if the 10 year old only eats cheese pizza and the 8 year old can polish off a whole steak. You might therefore want to stay with buffets and family-style meals.
In the MK, Crystal Palace is good breafast, lunch, or dinner, and you get the characters from Pooh. At Epcot if you need more character time there's Garden Grill, but I think the group would have much more full at the Biergarten in Germany. For an HS day, H&V is a very generic buffet; unless you really need the F! seating package, go instead to Cape May at the BC/YC resort for dinner (all you can eat crab legs and other seafood, as well as some standard meats and sides). In AK Tusker is great for breakfast; lunch and dinner are more Indian-themed which does not appeal to me so much. After your AK day if you'd rather take the bus to AKL, though, Boma (also a non-character buffet) has both standard foods and some really interesting choices - different spices, but mostly not fire-engine-hot ones.
Ohana at the Poly is one of the best 1-TS dinners, I think. Beautiful theming, great food that they bring to you (you get apps and sides family-style, and servers continuously circulate the tables with skewers of beef, pork, chicken, and shrimp), plus the best dessert in the world. It's a hard reservation to get, though, so make your ADR as soon as your 180 day window opens.
For an adult night, Signatures are lovely but pricey. I'd probably go with whatever type of cuisine appeals most in one of the countries in Epcot. Tokyo Dining is a much more quiet, adult experience (everybody takes the kids next door to Teppan Edo) if you like any type of Japanese. I prefer Tutto Italia for Italian but lots of folks like the pizza at Via Napoli. Restaurant Marrakesh if you want something really out of the box. Or just grab snacks and then have an adult evening at the Rose & Crown with Pub Grub rather than making an ADR at all.