We love eating all over World Showcase. I think Biergarten is a great suggestion for your 11 yo needs. Morroco too, with the band and Belly Dancer. We love the food there, it is a beautiful restaurant and the servers are warm and friendly.
We ate at San Angel Inn 2 weeks ago, despite all the bad reviews it gets here. I was very skeptical. However it was great. Good food, attentive service, and nice surroundings. I did not think it was too dark at our table, although the setting is dark. Your son might enjoy watching the boat ride go by if you can get a table near the water.
Teppan Edo in Japan is another great suggestion. You sit at tables for 8, with a large Teppan Grill in the center. The chef comes to your table and cooks (sitir fries) your meal and entertains you while he cooks. It is great we love it and it definintly would hold your sons attention. The food is great and the restaurant is beautiful after its recent renovation
Whatever you choose be sure to make an ADR well in advance, and have fun.