I doubt very much so that Disney would lose their liquor license. They have very strict policies and procedures in place to prevent underage drinking.
true, every single vendor has their own liqueur license. and not just every club, every single vendor.
just as each has their own name on the credit card readers (for example, "Liberty Square" market and "Haunted Mansion Ice Cream Cart" are two wholly separate locations, just right next to each other.)
Each individual stand/cart/restaurant, if it sells alcohol, has its own license. And the cast has to pass a variety of tests in order to serve alcohol as well. (my sister works in foods, i'm in operations)