I have the feeling that Fiona trying to protect herself from Nick may do more harm than good. I mean, he is concealing her land from the public and lending her a soul to take care of the bies, and he can undo the first one at any time if he so chooses. I'd say it's kinda necessary for Fiona to maintain a working business relationship with Nick (as unpalatable as that might be) because the alternative is worse.