If you wanted to keep the tenant you would serve a Cure/Quit notice to them to stop subletting and then you would have to monitor the house closely for awhile to make sure they aren't using it as an airbnb again.As far as losing this tenant, not much of value would be lost if they moved out.

They appear to have no obligation to cure title defects, but only to show that someone (their own title company themselves, owned by the same parent) will insure me against them.

Can a property manager at least "force" the hoarder to "cure or quit" to protect their property, the neighbors, etc.?

Bottom line: once you lease a property, you have NO choice but to provide a safe and habitable property with all deficiencies cured within 30 days. 

When I am talking about 1 out of 100, I’m speaking of an error made by the researcher or underwriter not covered as an exception thus requiring a claim that will cost the underwriter to either pay the claim or cure the issue.I know you misunderstood my statement there, so we’ll move on.  

It takes a long time to fully cure, like a month, but once that time period is over it’s a very solid paint, almost like a lacquer.

Well, closing off any penetrations will help but probably not cure the problem. 

The judge is not going to tell you how to cure your problem.

Maybe we'll be able to flatten the curve and have a vaccine or pills to cure or whatever. 

All depends on how they choose to cure the debt and the unforeseen consequences of those actions.