All sounds rather far-fetched. Yes, an ap on the phone or laptop for listening could be used as long as it is tied in with cameras and microphones in each room. Surely, if these had been originally installed, they would have been taken down now.
Also, nothing has been said as to the OP's own conversations with her hubbie about her daughter -obviously detrimental conversations!!! If that is how she feels about her daughter then the relationship is already damaged.
Like many others, I had to cancel my arranged visit for a few days to my eldest daughter - as that would have been during the week after Christmas. When I do visit her, I do very little,, keep my own bedroom there neat and tidy - but that is all. Equally on my visits to my bubble family near to where I live, I do absolutely nothing whilst I am there.
Surely, if a family member is coming to stay for a pro-longed period, then part of the arrangements with them would be a discussion on what they will need to do whilst living in that household.