Since my units are a C-class, I also suggest a drive-by so they are not unpleasantly surprised by the neighborhood when they attend the showing, and just keep on driving by anonymously as I wait outside. 

The operating company takes on all of the liability that would otherwise blow back on you including: paying property management, paying contractors, collecting rent, marketing, etc.5th pillar is owning everything anonymously.

hah...I mean, at least when I tried to make millions as an *Anonymous* Distributor in '91, I was able to sell some cleaning products, diapers, and one fake Christmas tree before realizing I had joined a multi-level marketing cult! 

.#2) Call up the local planning/building/zoning department and anonymously and hypothetically explain the situation to them and ask what the ramifications are if they found out about a similar unpermitted structure, etc.

Anonymity of property owner prior to suit creates the first stop-gap because it is a barrier to entry.

The point is you want anonymity, which means you want to harder to find, not easier to find.3.

I have a current client owner that is over 70 years old (and with permission) allowed me to share an anonymous profile. 

There is also the land trust which is a little different - typically there the beneficiary and the grantor are the same and you would get a separate trustee (mostly for anonymity purposes).  

Series LLCs are great structures to hold investments, and can be structured for anonymity to lower the potential for litigation. 

I'm not familiar with Washington state's property tax laws, but an anonymous call the the local assessment office could give you great insight without pinpointing the actual address.