How do you protect your clients from making the same mistakes?

I would also make sure you are protected from any clauses that can inhibit you from trying to execute your plan with the duplex.  

Thankfully I was protected by the moratorium so he couldn’t evict me for non-payment, so I was able to live rent free and didn’t have to pay utilities.

This is called asset protection.

Disability is a protected class under the Fair Housing Ammendments Act of 1988.

All change orders should be discussed (contractor should explain what additional work is needed nd why), quote it and then have you sign BEFORE said work is started & completed.Doing things in writing protects BOTH parties.

We have a 12 page management contract that we've added our real experiences to over the years, with the intent of protecting both us AND the landlord.

These folks have shown they're not willing to behave reasonably, so you need to protect yourself.One question: You said the property was supposed to be delivered vacant but was not.

There is a lot of development going on, and sure, while portland the city has strong tenant protections the surrounding metro area (and beyond) is different. 

As a consumer, you’re protected for sake of mortgage shopping.