Not sure why you couldn’t make them all contract employees. Instead of W2’s, you issue 1099’s. Each person that works there is responsible for his own taxes, insurance and fica: once you pay them, you are done with them and they can be terminated at will.
There’s a lot of ways around this stuff... never works
Why not require fast food workers tobhave a professional license, that enables them to work in fast food, like selling homes or cars?
You can then set a wage and hours, with at will employment
Evil thoughts breed evil solutions