I would suggest Margaritaville in Citywalk. You can make priority seating reservations even if you are not staying on-site. I did it on our trip last year and will be doing it again this year. They take reservations 30 days in advance. My two kids and two nieces (8,7,5,4) all loved Margaritaville and can't wait to go back again. (Look for the erupting volcano!). My son is always asking when he can see the volcano again. They have a kids menu (although it is not posted on their website). On the Universal website click on dining and Margaritaville has it's own website w/a phone number to call. There are also some reasonable counter service places in Toon Lagoon that the kids would enjoy (pizza, chicken).