Honestly, this lawsuit is laughable. James Earl Jones himself allowed his voice to be used to train AI before his passing, and his family has given their blessing on this implementation in Fortnite.
Besides, it's not like this Darth Vader AI is replacing any jobs; it's a chat bot, capable of giving live responses to players across many live matches ongoing around the world. Unless it is feasible to hire a massive team of Darth Vader voice actors to be able to respond to player requests to "force choke me daddy Vader" live across hundreds of ongoing matches while staying completely in-character 24/7, their argument about Epic Games "replacing voice actors with AI" holds no water.