On the early evolving story days, in Craig Miller’s book (pg.382) it is said that Fett was to be the main villain for a movie and that the emperor wouldn’t be shown until the sequel trilogy which was about (pg.375) which ever character survives movie ‘Three’. It really sounds like George/Kurtz/et al were conceptualizing writing everyone out. Harrison in carbonite, ‘the other’ could move Hamill out. Fett makes Prowse expendable. The above ‘Leia badly scarred’ seems like the way to move Carrie out.