If you pop Popcorn, you are cooking food. Therefore you need to meet the minimum Health Department Standards. So once you have met those standards, it takes no additional effort to offer Hotdogs (Make sure they achieve the appropriate temperature.) Cotton Candy, Nachos, Pretzels, and yes, Hamburgers, Fries and Pizza.
You will need a Three Compartment Sink and the fire department may insist on a hood, fire suppression system. The Health Department may insist on a grease trap and other items.
It seems wrong when you take over an existing site and then the Health Department insists on all kinds of new things. If you are building from scratch, then it behooves you to visit with the Health Department and the Fire Inspector and find out what they expect. Make it a working with experience instead of a working against experience.
Our older site is Grand fathered. But our Health Inspector is also a neighbor and an appreciative patron. But a new plex in town had to install an automatic fire curtain around an upstairs concession stand for the Fire Department. I think it was excessive, but that is what was required.
All new homes in Sonoma County are required to install a Fire Sprinkler system. Mine will have one.