I think you mean that if Aniston 'joined' the harem she wouldn't be like the rest of the staff or the mom/aunt?
Yep, I agree. I think Aniston could offer a lot of potential from being in the police, but the story might have to significantly ramp up with some unforeseen elements that happen to need an outside group to be brought in to assist.
I very much get the idea that almost everything that's happened has been staged to enmesh the MC in the situation so he'd never want to leave, and is deliriously happy. A happy mind is a productive mind and all..

Lisa (the lawyer) seems to be the main one behind the planning, based on how she was able to bring in both aunt directly and mom through her friends and relatives.
I can't wait to se what sort of 'celebration' they will have if the MC is able to finish that battery tho... Hmm, house wide orgy that lasts a week?