as of right now there is no official plan for a line going to WDW. at least from what i have heard/seen. and the company I work for works directly with the OIA regarding that terminal expansion.
Even if there was tho, the project wouldnt be finished at earliest of 2021-22 (being generous) for a line to Disney.
However if you ever get the chance to visit that terminal, check it out, its really really nice. the APM however is not that great and ironically i would say is more bumpy than Disney's old monorails.