I don't think anything we see of the Others is real. I think it is all staged one way or another to make any one individual, or a group of individuals, think that they are something they are not, i.e. authoritative, law-abiding, communal, etc.
I think it is all staged, even the "family" impression Ben likes to give people about him and Alex.
So, is Juliet marked for death? I highly doubt it. I think it was a way to let her gain Jack's trust. It was a way for her to let him think he needed to take care of her.