I'd stick with counter service or buffets.
In all honesty, a trip to WDW where your kids are probably off schedule and over stimulated to begin with is not the right time or place to expect them to sit through a full service meal.
If you really must go full service, my suggstion is to feed the kids at a counter service place first, take some quiet toys to keep them amused, and be prepared to leave immediately if they become at all fussy or disruptive.
Anne