No they don't need to know everything but they should probably have a general idea of at least somewhat where it's going you know what they start to write a script you think they'd have an idea of where the trilogy would end but this Trilogy feels like a 4th grade writing assignment where one kid starts and then the other kid continues like oh the dog walked into the room and now there was a lightsaber there
A fourth-grade writing assignment that has done roughly $3.5 billion at the box office. I'm sure Disney would love more of those.