I've definitely read 'Rita Heyworth...' and 'The Body' before. Not sure about the other two. I'm guessing not, though, as 'Apt Pupil' didn't ring any bells when I saw the film.
Seeing as I'm dragging my feet enough with the reading and, subsequently, these posts, I think I'll do a separate post for each story/novella. Don't hold your breath.
Thanks for reading.