Unless, you are willing to put in major, major time, and get boots on the ground, the chances of you getting screwed (or doing a deal that is very marginal at best)  are very high.  

But to build a unit without permits or inspections is what the guys who faced the Ghost Ship fire in Oakland did and take a look at how screwed they are now...

Son bull said to papa bull "Let's RUN down there and screw us a cow." 

I don't even want tenants to fill holes with spackle because they screw it up more often than not.Go to Google and search "lease agreement .pdf" and you'll find plenty of samples from around the country.

See Even when we screw up in this business we are still on track to doing better than 99.99% of the population because we are building wealth instead of sitting on the couch wishing , with our fingers crossed, that things will get better and life will pan out for us somehow .

Also they left without even telling you, screw them,,,, I would tell them  good luck in court you left without even telling us . 

Don't make it harder for the rest of us by screwing this up even more.

Even when it's best to sell, often times one party just wants to screw the other over.

You just screwed up on your calculator.

Most private investors are cultivated through relationship building and unlike HMLs, they are not prepared to step in should you screw up.