Everyone's ideas are very good! I'm sure they're all a part of the story somehow!
Welcome back Alice! Yes, FS did always want to be an actress. If she seemed 'refined' she was either acting (hey you can be coaches, like My Fair Lady) or as FA said, maybe some people just saw what they wanted to see.
But really, just about anyone can put on an act if they have to. What about job interviews? Court cases? Meeting the prospective new in-laws? It's not that hard to pretend to be something you're not. I have an aunt who is very prim and proper, and every since I was a kid, whenever we visited her, we were told to be on our best behavior. Boisterious, noisy, joking, playful, even sloppy people became quiet, calm, reserved, well mannered, even prissy. My Mom used to call this being "Mae Correct" If you met royalty, you'd do the same. If you met a favorite rock singer, you might be more loud, or act 'cool.' I think this is something anybody can do if they want to.