Is Anna actually a ghost? Did she implant memories in the family's heads to make them think she's theirs? Or are we just going very hardcore on the metaphor here?

No one ever notices her coming up on them, even when she calls out. Her looks are described as stereotypically ghostly. Her family (and herself) talks about her as if she's extremely listless, irritable, dull, and no thoughts of a future. She's the only one who seems to know anything about Italy. She also immediately starts to see and hear things. I dunno, but I'm suspicious.

Also, what is up with all the anti-intellectualism in this family?? Don't ask how something is pronounced if you don't want to know. Also, there's nothing wrong with someone talking about their knowledge in art when they're an artist and you're talking about art. Like, jesus. The inferiority complexes in these people are insane.