I'm bringing my 5 month old in June for his first trip (his big sister's graduation trip) and plan to ride everything he can ride. Well depending on his mood of course. We live on the Gulf Coast of MS where Mardi Gras is prevalent and I took him to a couple of Mardi Gras parades when he was around 4 - 6 weeks old. The noise didn't bother him, he actually was very interested in watching all the excitement of the parades. I don't plan to watch Wishes in the park this trip but will see it from the restaurants where we have reservations made for those nights so I'm not sure if the loud fireworks would be different than the loud parades. Of course, he can sleep through noise and it doesn't seem to bother him.
I'm hoping he will like the characters and not cry but if he does, then we'll see how he does once he's older.