I think that the American and Eve would be too obvious.
YY to the dad! There was something about strange about their relationship. Or maybe the mum - she knew what was going on with the dad and was jealous because she is horrible too?
Or... maybe the sister. Maybe she had a crush on the American and set fire to the barn to get back at Lucy, thinking it was Eve in there. Or maybe not caring which one it was. Bit strange that she doesn't remember that entire year otherwise, surely?