"I'm sorry to disturb you, you may not be the right person for this

If you think she is disturbed you could ask for a welfare check by police when she acts up.

In order for this to take place a squatter must prove to a judge that he or she has possessed the land for a minimum of 15 years without any disturbance or request to vacate from the rightful owner.

Ask your tenants to file a police report regarding the vandalism to their car and to let you know of every disturbance caused by the people in the neighboring unit and their invitees.

I myself have considered carrying a sign at one of those "free" seminars but I do not want to be arrested for "disturbing the peace". 

In essence, they need to pay their rent, not create any disturbances in the property to impact the other occupants and not violate their lease and use the premises for illegal purposes.Also the Bill does not specify a time-frame to declare oneself a victim.

Best not to disturb it with a  cash out refinance 1st mortgage but you still need access to the equity. 

The more people have to share bathrooms, the less comfortable the housemates will be, and the more problems you'll have.A layout that makes each bedroom relatively private and isolated--for instance, a bedroom that's down a hall and around a corner from the kitchen is much more private than a bedroom RIGHT NEXT to the kitchen, living room, or other high-traffic area.A layout that minimizes the amount of traffic that goes by the bedrooms--for instance, a bedroom that's right next to the front door sees a lot more traffic than a bedroom at the back of the house.Multiple floors, with the bedrooms and bathrooms on separate floors--for instance, I have a 3 story house that has 2 brs/1ba on the bottom floor, 2 brs/1ba on the middle floor, and 1 master suite on the top floor--this makes it so that no more than 2 people are "living" on each floor, and one person (the master suite) has a floor all to themselves--this provides a lot more privacy and living space for each person compared to a 5 br house where all br's and ba's are on the same floor.Multiple exterior entries/exits in locations that allow tenants to come and go with minimal disturbance to the other housemates.Carpet greatly reduces noise, whereas hardwood floors (especially old ones) can be very creaky.A large kitchen with plenty of food storage space (and perhaps even multiple fridges and dishwashers) will be much more livable than a small, cramped kitchen.Sufficient parking will be important.Ideally, an HVAC system that allows each housemate to control the temp in their room would be great.Closely consider what types of tenants would want to live in the property.

We had a common door bell on a 5 plex, next to mail box was push once unit one, push 2 times unit 2, 3 for 3 ...ect.. the buzzer was in main hall and served the purpose.. otherwise they pounded on the main door and the first floor units were disturbed..Not perfect but it worked.  

I do appreciate the sellers trying to make this work and from their perspective it is probably best interest to not disturb the tenants or get them angry.