My take:
Walt fully intended to build a MK in Florida. Even in the same spot as where it was built, both EPCOT and the MK ended up pretty much where Walt planned them, as below in the pics. Walt's plans for both were still vague, his concepts rushed for the Florida legislature and sponsors.
In this early stage of the Florida Project, and the final stage of Walt's life, Walt himself wasn't very interested in the new MK, his thoughts preoccupied by the other areas.
But both the company's pr and the general public are quick to conflate Walt with TWDC. Walt may not have expected to be busy designing the MK, but the company would. Walt didn't film Mary Poppins, he didn't draw Cinderella, he didn't write 'Comics and Stories'. And Walt didn't build Disneyland. His company did, as it would build the MK.