E.B.
Chili can be delicious, but it's important to remember that with chili there's an increased risk of spills and mess, and you need to remember bowls and spoons. And it's harder to transport (not impossible, but more difficult).
I'd stick to handheld choices. Kids tend to run around, and keeping the food choices to simple options that little hands can handle.
Hot dogs are a great choice, and they stay warm in a crockpot for quite a long time. A few bags of buns, ketchup and mustard and relish, and you're done.
Make the corn bread into mini-corn muffins, and again, you'll have a kid-friendly hand held side dish, and eliminate the need for cutting up a large pan of corn bread. You can make a ton of mini corn breads in mini muffin tins (or larger regular muffin tins) a day or two before the party. On the day of the party, just brush the tops with melted butter.
If you like chili and really want to serve it, how about in the form of meatballs? Make meatballs using your favorite chili seasonings (cumin, chili powder, onions) and pile them in a crockpot. Serve with buns, or just have toothpicks for skewering them. If you look up Tex Mex meatballs online there are many recipes.
My opinion is that popcorn would be really messy (a lot would end up on the ground). How about sticking to individual potato chip bags - those large multi-packs of variety-flavored chips that they sell for putting in kids' school lunches would be perfect, and much simpler.
Bring garbage bags, but not a garbage can. Bring duct tape and you can tape the bag to something (a pole, etc). Bring a couple of containers of wet wipes for hands and faces.
Have fun! It sounds like it will be a fun party for your son.