Check the voting rules in the by law and declarations.

But I elected not to claim depreciation on the house and never declared it as a depreciable asset on any business tax forms. 

Ignoring foolish solicitations is a muscle worth exercising.

After healthcare being declared a human right. the other shoe is dropping: according to the latest demands from the Bay Area , California is trying to mandate housing a human right.

It wasn't until we had our declaration reviewed by an attorney that we found out the rule would never hold up in court.

If ANY personal items of the resident are left behind,  either a signed declaration from former resident that they have moved out and release any claim all remaining items - enumerate any large or potentially valuable items - (get it notarized or ensure signed with witnesses present)  or preferably,  ensure property is completely empty, interior and exterior,  of resident belongings.    

How would this be declared/explained to the IRS...or is this in any shape or form prohibited?

If you get to court, you will pretty need to declare everything anyway. 

The big builder attempted to muscle me at the end of the build, but I hired an attorney for a few hundred, and they sorted it all our with something I never though about.

Those renters who bailed without paying rent will likely declare bankruptcy.In the final analysis, the victims are small mom/pop landlords and MF Cos. who will have to liquidate the Real Estate assets to protect themselves from bleeding furthering the crisis of liquidity in that Real Estate Class.