We were on Europa last June with our family, including a six year old and two 12 year olds. In the MDR, the kids usually ordered off the regular menu but had the kids menu (similar to those posted by Essiesmom) to fall back on if there wasn't anything they liked. While the adults went to Butchers Cut, the kids did not so I don't know what is available in that specialty restaurant for kids. We all went to Hola! and Kaito Teppanyaki & Sushi Bar and all three loved those two restaurants.
Enjoy your trip! It really is a beautiful ship!