Numerous rates could be raised, though it is uncertain until we have any sort of idea of who is gonna take what. I'm hopeful, though unsure, that there has been some planning done in the case that this would happen. The debt is likely gonna try to get passed around like a hot potato. That would be a large amount of debt to add to any counties books. Though my guess is that a solution to this issues is that the taxes can fall now on the 2 cities which make up RCID (which essentially outsource everything now to the RCID) instead of necessarily going to the counties. Still, that is a difficult transition and a lot of legalese will have to be worked out. But for example, utilities aren't going to be a huge deal. Disney fully owns the energy company that manages the energy for the entire district, Reedy Creek Energy Services. That won't be going away regardless of what happens, though they'll have to "negotiate" new contracts.
Still, it is uncertain what services will have to be taken on by the counties and what can be handled in a new bureaucratic apparatus of the cities (if they can handle anything in the short period of time the district would be dissolved by). The cities right now are essentially legal shells, with all their authority vested in the RCID. It takes time to transition services, even on paper. Most people have no idea the legal and bureaucratic challenges involved in provisioning local government services.