One can not convert a motel (c1) into multi without a rezoning, traffic, impact study by the City.

Any other ideas on how to track impact on real estate?

What worries me more, is the Arbitrage lovers here who keep saying "no problems" to newbies as if risks are not an essential part of a business.

And how can it impact the housing market?

You have a nice asset here it seems that allows you to live essentially for free. 

Any kind of applicable hotel tax for short term rentals, as an example, would still impact an IRA.You should check with your plan provider and your local CPA.

THIS SUMMATION DOES NOT INCLUDE ANY OPINION REGARDING THE PHYSICAL CONDITION OF THE BUILDING OR IT'S IMPACT, IF ANY, UPON THE VALUE OF THE BUILDING.

-Minimum of 800 ft.² so if your house is 1200 square-foot you can still build an 800 square-foot ADU.Bill 670-Eliminates HOA’s from regulating ADU’sBILL 12-illuminates impact fees on ADU’s 700 ft.² or less.Bill 68 -If a property is zoned as a single family living home. bill 68 allows you to have three rental properties on it now.

The availability and prices of building materials could be impacted for new development, but for existing real estate and long-term buy and hold rentals, I don't see a major impact.

Yes you are essentially using an ARV approach of sorts.