Rather than pay $20 for a cheap crappy umbrella at the festival, bring your own compact travel umbrella.
You are allowed to bring a soft-sided cooler (12-can size or smaller) and I recommend you don’t forget this.
Pack lots of water and stick the cooler into the stroller bin so your shoulder doesn’t get sore.
Instead, you’ll be treated to culinary delights such as crawfish bread (DEFINITELY try this one, even if you don’t think you like crawfish), sausages, alligator pies, po-boys, etc.