'Ohana is at the Polynesian and perfect for young kids. It's character dining with Lilo, Stitch, Mickey (and someone else... I forget).
If you want to take a monorail ride, the Grand Floridian has 1900 Park Fare, another character dining option (kind of random face characters at lunch and princesses and friends at dinner).
Then the Contemporary has Chef Mickey's - Character dining perfect for young kids (Mickey and friends).
If you want a break from character dining, you might try the Grand Floridian Cafe or the Wave. Then there's California Grill atop the Contemporary - they turn down the lights and play the soundtrack for the fireworks at MK.
The Poly is a very handy resort transportation-wise. Great choice. Have fun at WDW!