They're already using similar tech for the Mickey meet and greets and the Galaxy's Edge stormtroopers. The details aren't public, but it seems to be a mix of complex dialogue trees with interrupts or context switches, controlled in real time by the actor or operator.
That's interesting; if you're doing human in the loop, I would have thought it'd be easier to just do voice swapping. Or did the technology not quite line up?
Someones linked in this thread the Defunctland video essay on these characters that I highly recommend watching since it goes into this in detail.
But the main reason is, there's a lot of brand imagery on the line with these interactions, someone putting on a voice, or using a voice changer could make a mistake. Disney instead have a conversation tree with pre-recorded voice lines that a remote operator can control. Much harder to mess up
And possibly more importantly, much easier to keep doing for hours on end. There's no need for a highly trained actor.