I'm assuming a TOPA is similar to tenant estoppel, due to them not having a written lease they are month to month tenants and those regulations apply, so keep that in mind when doing your research on local laws

See https://noprop10.org/On AirBnB in San Francisco - The City of San Francisco has strict regulations on AirBnB in the city.

If you do not learn/memorise the RTA regulations before you invest you will be making a major mistake.

I am not familiar with California regulations and tax rules.

Where I’m located (in Virginia) the local development department (building/zoning/etc.) handles storm water regulations and enforcement.

I do prefer to work with one in AZ to keep AZ laws/ regulations in mind.

Many countries regulate the flow of money in/out of their country.     

But who/what regulation makes it a requirement?

Can someone provide some guidance and possible struggles I may experience with acquiring a construction loan, building costs, selling regulations etc. 

After two renovations in other properties, I sold my own apartment in 2007 through an incredibly complicated series of contractual maneuvers designed to skirt EU  banking regulations, and the bank was as in on it as the buyer was.