Eventually you have to take action. 

Sooner or later the right property will come across your lap and you will take action. 

He had no idea I heard his conversation he had a few months before.Heard nothing from him for several months and got a letter from a local attorney threatening legal action unless I pay $10K.

However, there are no metrics I see right now, along with the actions and proposed actions of the federal government that would indicate to me that housing supply will drastically improve, or interest rates will drastically rise soon, that would lead me to conclude property prices or rent costs won't drop in the near future.

It let's them know the clock is ticking on them paying the rent before you start court action.

And also what actions in your life would you say have helped you the most in terms of personal growth?

I won't pretend to fully know what action to take, besides the obvious, hire an real estate CPA!

If the low score one has a lot of landlord tenant action (not just on credit but on background) we may pass as it may imply they were the ones on leases in the past. 

Do not have any experience with this, but the letter threatening legal actions should do the trick.

Its just a matter of how far removed the consequences for your actions are.