Crowds may be a slight bit higher than normal, but not much excluding the concert nights (Usually Saturday night, maybe one or two Sunday night concerts.) which could be very busy around concert time depending on the act (8PM ish)
The food doesn't change, they do have an outdoor food section in the New York area of the park with various new Orleans/cajun style foods. But it's just in addition to the regular foods they have. Things like Jambalaya, Gumbo, Po' Boys, beignets, andouille sausage, king cake, rice & beans, and a few other things like flavored (or plain) chicken tenders, cheesesteaks, and a couple other selections I forgot. The parade is most definitely worth seeing though, and very fun. They are doing the parade often enough this coming year it might be possible to get on the floats to toss beads if you go over by the Day at the Park with Barney show area around 6pm.