Duplex have different zoning that may permit additional units.

There are a few different avenues that my clients have been exploring, including getting unpermitted units actually permitted.

The owner can designate a host who shall be responsible, and authorized, to act on the owner's behalf to promptly remedy any violation of these standards or the permit.

You may could give them a license to use the land, provide a temporary or revocable easement or otherwise permit the use in some way.

That is more likely to happen with a blue-collar, middle-class worker than it is with a wealthy person.

FWIW Its California , you probably need a permit  to do just about anything as long as you pay the fee 

In order to comply with SEC regulations, there is no platform to publicly announce your deal to the crowd (both posting on Facebook and publicly announcing it at an event could be construed as a solicitation, which is not permitted under the structure that most sponsors in the group use).

It could be worth transitioning to a midterm rental if there's demand for that type of housing in your area, like traveling professionals or remote workers.

GC never pulled any city permits yet charged me (didn't find this out until the job was finished). 

My goal is to switch to these workers as they have a steady paycheck.