If you want to stick to counter service in Epcot, I suggest the following .....
The bakery in France as a fabulous ham/cheese croissant, quiche and cheese/fruit platter. And of course the desserts.
The bakery in Norway has a selection of sandwiches -- smoked salmon, turkey breast, ham/cheese and salads. And of course desserts.
The Yakatori house in Japan -- is very reasonable and you get a lot. It's overlooked by many people because its not near the other shops/restaurants in Japan.
Just a suggestion, but I find when you do the math, a counter service restaurant can end up more money than taking advantage of the luncheon specials at a sit-down restaurant.
Chef de France has a lunch special for $14.95. Soup, Salad, a Sandwich and dessert. You could make this your big meal of the day.