Long story short, I put in a claim with the state and they settled with me after many phone calls for a dollar amount and did considerable work to the new road (new grading, storm drains, & cleaning the outlet a block down) and my property (retaining wall, moved my driveway, etc.) to help remedy the situation. 

@Fareed Khamitov I agree with @Jaron Walling that you are not in any rush, you're in a great spot financially. 

I will use a licensed contractor to repair the HVAC, run a new electrical circuit, or open up a wall, etc.

It's a five day course but I work full time and don't want to waste my time and money. 

If it's no longer r6 you'll likely end up wasting your time. 

I will ask them to wash the walls before they move out but I doubt all the filth will come off.

Writing checks would be tedious and a waste of time.

Squatters has broken into all 4 units and pulled out plumbing and broke walls between units.

Old loft apartments in a brick building with tall ceilings, brick walls and wood floors. 

A few bandit signs is wasting your time.