It sounds like the plumber took advantage of the situation. second… Many property managers wouldn’t know much difference between a hammer or a screwdriver so expecting them to go assess the situation is not practical.

Then, you can assess if what you have to do is worth your time."

Consulting with a zoning attorney is advisable to assess the feasibility of your project and guide you through the necessary procedures.Hope this helps!

I would encourage him to take a lot of time to assess, take small risks at first, and learn as much as he can along the way.

The IRS has said, since 2017, that the improvement ratio or $ value is what your taxes are assessed as, unless you have a really compelling reason to use a different value. 

Also, there's the added risk of being compliant with federal regulations & state laws as well as properly assessing/vetting both the borrower and the property.

Didn't mean to get political but I generally vote no on anything that will cause more rent control or increase my property taxes (all the special assessments).  

Do I consider it as an SFH and assess potential rental income based on SFH?

I have heard it’s cooled down quite a bit and assessing if it’s still a worthwhile option to consider as a market for str or even mtr? 

Otherwise every vacant lot would be assessed to have a multistory building on it.