If I work at one of the parks and I want to transfer to work at amc at downtown Disney, can I do that through casting? Or do I have to fill out an application online?
Correct. AMC, like most of the stores and restaurants at DTD, is just a tenant and not a Disney-operated vanue. They handle their own hiring. Some people choose to work part time for Disney and part time for one of the many non-Disney operators so that they get more hours overall without hitting an hours cap. The employees of some tenants get Disney perks and some do not, but in general they are significantly less than what Cast Members get.