@Leo GregoireTo answer your question directly about cash for keys:In rent-controlled states like California, you can sometimes pay 10 to 20 grand a door to get them out.I have never had to go this route before.

If the crime is so bad and the homeless is out of control along with the chickens, why is the rent still so high?? 

It’s got some termites, that I will be signing a pest control company on to do treatment for.

Situation was beyond my control.  

@Heather FultzCondos can have the advantage of the maintenance of the outside taken care of but can run into issues with HOA and restrictions on STRs that you can't control. 

But if this is not the case one option would be to seller finance that way you can have control of how much income you are getting every year.

They are out of money or the banks are going to take control of the buildings and nothing is going to happen to them as they are getting their pound of flesh while the stakeholders are getting nothing.

Holdover tenancy is addressed by a significant rate increase for every day (I use 150% of market rent as that seems to be a reasonable enough number that a court would allow + costs associated with their refusal to leave) and I have wording that if I can't turn over the unit for any reason outside my control, I'm not liable. 

When i ask my property manager about it the response is that i must talk to rates department. rates department blows smoke and tells you they cant control airbnbBut wait there's more! 

@Irving Vizcaino First I would use Mold Control by Concobium.