The billboard would remain the property of Lamar unless you terminated and they failed to take it.

I bought a property last year in WA  state and the lender failed to foreclose for 10 years.. and the lender just mailed the owner their deed I had never heard of that before I guess there is some statue of limitations as to when a mortgage or deed of trust needs to start an action once default has occurred. 

If they failed to collect them, that is their problem (and their job). 

Which 95% of everyone fails or gives up in every field (wholesaling, investing, rehabbing, selling, development, etc.)

Sorry, but there is a reason so many people fail in business and it is because they believe and trust the wrong people to help make decisions.

If you fail to perform they could always put a lien on the property as protection.

That's where most agents fail.

If it's your first time doing one of these projects, you may want to hire professionals for certain aspects of the job that could have you fail an inspection, hypothetically.

If the numbers work and you've got someone experienced looking over your shoulder, it's hard to fail big.

It's also wise to avoid being a crappy human being, which is exactly what he'd be if he had video evidence of domestic abuse and failed to act.