Basically common contract or agreement law.

Or, ya know, just spend the next 140 hours trying to get a self-study law education followed by another few hundred hours self-study to sort out how to avoid repeating the situation.That's the reality of it all. 

depending on how backed up the county is it can e take a few months for court date. in essex county it took my mother in law about 8 months or so for the full process. she had an attorney, not sure if that sped anything up

Of course, with all things, the answers to all these matters will depend on the circumstances.California tends to have more laws on the books and requirements and restrictions that it can be a good idea to form a CA LLC for out of state property so that you as a CA resident are covered, and to try to have your contracts fall under the purview of CA courts.

Newton's law of tax: What goes down must come up.Everyone enjoys the sweet benefits of bonus depreciation, but what happens when you sell?

Should We:Sell, take advantage of the capital gains law, move, and pay the mortgage off on the new house, credit cards, etc…?

I think it will also depends on state laws and a lot of information not present but the HOA rules and insurances are two different things.

The tenant laws in New York make life as a property owner way harder. 

If you are a legal property manager in your state the owner should have the unfettered ability to allow you to act as his/her agent to enforce the lease, whatever provisions they may contain plus whatever your state laws allow.

As others have stated, there are Income discrimination laws in Kansas City so if you are an investor with rental properties in this city, make sure you understand the regulations.