So what might change, now that Vivien hires Luke to help with security? Clearly, he lends a hand with the angry Hayden, and can cart her away, at least temporarily. But now he's going to suspect some stranger happenings, considering that Hayden disappears from his patrol car as morning breaks. It doesn't make a lot of sense that a security guard can provide much protection against the dead. But if he knows what's really going on, maybe he could be some sort of help. If nothing else, it will give Vivien some peace of mind.
She'll need all the peace of mind she can get once she's in the house alone without her husband. Now that Vivien has kicked out Ben, it makes her all the more vulnerable. True, Vivien is a tough lady, and can take care of herself. But when facing off against ghosts, the more help one has, the better. Without Ben around, that is one more protection that she doesn't have. Or maybe she's safer without Ben, considering what the house drives Larry to do when he lives there.
Larry must be permanently changed by the house, unable to leave it, unwilling to stop interacting with the current owners. Larry is probably not a ghost, because Ben interacts with him outside of the home in a previous episode. But he still looks like he's from another time, and is heavily involved in the goings on there, like Constance. Thus, Larry is likely to keep going after Ben for money, if for no other reason than to stay involved. How soon until his continued presence tips off Vivien about Hayden's fate, and Ben's part in it?
For anyone who likes a good scare, or a decent mystery, American Horror Story is a series to watch. Having just been renewed for a second season, like its ghosts, it is not going anywhere.