Best ideas for parade food? We will have an ice chest and a coleman burner.

sandwiches - with a flair of course!

Cold pasta salad, chicken legs, rolls or corn bread muffins...
I would forget about the burner as you will spend all your time staring at it and not the parade!

There might be laws against using the open burner in city areas.
I'd go with picnic food; soups in thermos, cold fried chicken, slaw, snacks (like the mentioned popcorn), Hot chocolate, coffee..etc.

Grilled cheese and vegetable soup!

Kettlecorn?