All vehicles have to conform to the basic DMV rules for your state.
This will include lights etc at specific heights, windshield and safety glass, bumpers as well as performance requirements and licensing. Some of these may be waved for some cars in the "specialty" class.
You should be able to get the specs for your state through your local DMV or from AAA if you are a member. They are most likely available on the DMV web site.
I'm not sure what you are calling a "mini car" but vehicles like those used in parades aren't fully street legal and can't be operated on public roads outside of special events.