As long as there is no "healthcare" being provided (medicine, baths, etc) then it's not regulated by the department of health.

That usually creates a big supply of rentals on the market that it 's hard to be absorbed and create a race to the bottom in prices, as all the properties are pretty similar and in brand new condition. 

A break even into a profit, and a profit into a windfall. 3- Capital - I used to state this as access to capital, back when the rules were loser, the regulations less onerous, and information less readily available.

There’s just not enough ADU supply (IN MY AREA) for appraisers to base off of.

Much of my career for the last decade has been in Cybersecurity, and we feel the same about DOJ and regulations around incidents. 

As more people placed more properties in STR inventory, and as more municipalities taxed and regulated the industry, the profitability of the overall industry has reverted to a much more aligned (lower) risk adjusted return.  

With the fires, labor and materials are going to be in short supply.

What are the best methods to independently verify zoning and land use data to ensure compliance with local regulations?

There are a lot of jurisdictions (most of the West Coast now) that include marital status, sexual orientation, and others under their fair housing regulations.

Infrastructure (eg water, sewer, electrical supply to the house) should be the landowners' responsibility.