You seem to have been a bit ignored! Probably by now you will have trawled through the rest of the forum and got quite a few ideas - but here goes with our experiences ..
We have stayed in January before - the weather has been extremely cold so wrap up well.
We have done character breakfasts each year - they are great fun and at four your child (boy or girl?) is probably old enough to cope with the gigantic size of the characters.
We go to DLP for the food! Blue Lagoon is brilliant - right on the Pirates of the Carribean ride, enough to see to keep any child occupied, and the food has always been good. In Silver Spur steakhouse you can watch your dinner being cooked. Rainforest cafe is fantastic for children (although I have heard that some are scared by the moving animals!) Annettes diner has the roller skating waitresses.
None of these is particularly cheap - what we have done in the past is make our children eat and eat at breakfast, (free) and then book the latest dinner possible, then they starve until breakfast next day. We do get a few snacky things(and drinks) from Auchan at Val D'europe to save money.
The only experience we have of NBC is the bar (!) - which is lovely - we always have a bar crawl around the different hotels!
Have fun!
Liz