Thanks for your advice! We'll be staying at the Poly during our time at Disney. I originally thought about Sci-Fi for lunch and 50's Prime Time for dinner. I had comprised a list of these 9: Ohana, 50's Prime Time Cafe, Boma, Beach & Cream Soda Shop, Coral Reef, Flying Fish, Liberty Tree, Narcoossee's, Via Napoli. I have read good things about these places. But also considering Hoop Dee Doo, Cape May Cafe or restaurants in DTD if we make it there one day.
If staying at Poly:
-- 'Ohana - seems like earlier the better for food quality at dinner. View of fireworks from just outside restaurant is excellent. We've never been to Stitch breakfast.
-- 50's Prime Time - huge portions for most things. 10 y.o. may not understand nostalgia and formica. The antics with waitstaff are not for everyone. Sci-Fi may be preferred by the 10 y.o.
-- Boma - a long journey for food, but AKLodge is worth a look. We prefer animal views at Sanaa over buffet at Boma in daylight. However, breakfast at Boma is special, but not special enough to miss Park time if you have to travel far to get there. Disney does not make resort-to-resort easy on Disney transportation. If this is your AK day, Tusker House offers similar flavors and you get Characters too (Mickey & friends, sans Minnie).
-- Beaches & Cream will work best for you if coming/going from Epcot or Hollywood Studios. It's nothing too special, but a meal in an inviting old-style ice cream parlor that is welcoming to a 10 y.o.
-- Coral Reef - only Nine Dragons is to be avoided in Epcot. Coral Reef can get mixed reviews that seemingly lean towards negative, but we enjoy the smaller portions and fish centered menu (Trout w/ beans & greens) and the view.
-- Flying Fish is fine, but we prefer seafood and ambiance at nearby BlueZoo. But BlueZoo is not on Disney Dining and that might matter for you. Again, Camp is free at BlueZoo.
-- Liberty Tree Tavern - location, location, location. MK is not known for their table service meals. I'm not fond of Thanksgiving dinner, so we prefer Be Our Guest at dinner. But LTT is well-themed and a good value.
-- Narcoossee's - the New-Englandy seafood-centered menu works for us. It can be pricey if not on
Disney Dining Plan or not using Tables in Wonderland (available to Annual Passholders). Like 'Ohana, audio for Magic Kingdom fireworks are piped-in and expect to stand outside to view. While we've never done it, you can walk a long path between Grand Floridian & Polynesian - which may be better than looping back on Monorail.
-- Via Napoli - only Nine Dragons is to be avoided in Epcot. The food at Via Napoli gets excellent reviews. However, gluten- & carb-rich foods of pizza & pasta are avoided by our family, so I cannot offer personal advice. But those huge pizzas get rave reviews.
-- Hoop Dee Doo - I believe there's a boat from Polynesian. Fun for children of all ages.
-- Cape May - I like Goofy, so breakfast works for us here, but not worth traveling from Polynesian in the morning....unless going to HS or Epcot. But if going to Epcot after breakfast, you'll have loooong wait for either Soarin' or Test Track. If going for seafood buffet - only worth the trouble if you are looking to enjoy the stroll along the Boardwalk too. Better seafood at nearby BlueZoo, and Camp for 10 y.o. is free.
-- Kona - if staying at Polynesian, the convenience of Kona should not be overlooked. I'm not sure there is any place that serves such good food for all three meals (breakfast, lunch, dinner) any other place at Disney. Unfortunately, the memorable sweet breakfasts do not work for my high blood-sugar, but Kona should get worked into your selections.
-- Downtown Disney Springs - if it fits your budget, Cirque de Soleil is a delightful show. Also, Disney Quest is fun for a 10 y.o., and adults might like it too. Some of the 'hotel packages' come with admission to Disney Quest (as I recall). Splitsville has surprisingly better than average food to go along with bowling. House of Blues is well themed. Newly opened Boathouse may be better value than Narcoossee's, although, we have yet to dine here. And if Beaches & Cream is on your list, you may also consider grabbing a sandwich (or something small) before a stop at Ghiradelli for ice cream while in Downtown Disney Springs.
Be advised about Downtown Disney - keep looking at DisBoards - all the road construction makes coming/going difficult, particularly on weekends and/or if planning to arrive at dinner hour. I'm not suggesting it should be avoided, just that you plan accordingly.