Their requirement for permits differed from what the law requires.

VERY expensive to build these and getting permits very tough ..

Although we weren’t changing the exterior, we were asked to provide a survey of our property, elevation drawings, stamped FAR calculations, and sat in front of the city councils to obtain an approval (the special permit).

The past couple years they have been tightening up on giving permits for STRs but this year they have the jubilee happening so they haven’t been as hard on it but that could easily change after especially with the move Spain just recently announced and Venice and Florence are cutting back as well.

Because the answers to these questions are site-dependent, you'll need to check with your local zoning and permit departments. 

Varies based on contractors, location, permitted vs. un-permitted.

Got permitting done to turn it into 3 units and it’s now cash flowing every month $2.5K.

QOZ property includes interests held by the QOF in a Qualified Opportunity Zone Business (“QOZB”)An investor has 6 months from the sale of a property to invest, and the rules permit actual receipt of the sale proceeds.

Pulling permits, hiring licensed contractors, being someone anal about the carpenters/cabinet installer/tiler/painters work.  

You might have to get an architect and pull permits for the work your describing.Eric