They are elderly, healthy, retired, live very comfortably, make minimal to no noise at all, very clean and they pay on time all the time.

You have to understand not everyone is an entrepreneur.If they work and take a paycheck every week that is their mentality.Work until they can't and HOPE retirement and the government will take care of them in their elder years.Sadly that isn't going to be the case.

If you mean by "passive investments" a CD, MM or other totally passive investment, some folks are elderly, disabled or otherwise unable to actively do anything, the YUCK is them not being able to be active, not their investments.

Locally, an elderly gentleman was bit on his porch by a large dog and eventually died.

His elder mom passed away and his dad was moving in with his son. 

Morally I couldn't kick her out but maybe I could rent out the other room to another disabled elderly woman?

You've become one of the 'village elders' here on BP based on the fact that you've seen and heard most of what's been posted; and you've posted over 1200 times yourself, so you've obviously been party to some great conversations.  

If the seller is elderly, the court will side with them.

HOWEVER, it is a heavily elder community so there are a lot of homes probably owned by inherited family members or the owners may need to move into a nursing home.

A quick google search and I learned it was the house of an elderly person who had been harassing neighbors (kids and adults walking by) for years.