Or maybe a streamlined lease that is compliant and enforceable?

May be irrational exuberance @Russell Brazil, however, this company is unlike any other RE company and given it's cloud-based office, it not only saves on overhead costs but also is COVID-compliant! 

here is the scenario, my friend is foreigner who not live in US, he wants to buy the rental property, I will help him to management it, he can give me the power atterney to handle all rental related issue, I have no license yet, is that compliant with CA laws?

You will need to implement a time sensitive task list for maintenance to assure all inspection work is completed so you do not loose any rents for non compliant units.  

The tenant turned the screened porch into a bedroom, which is clearly non-compliant.

That’s when you learn you either tear your house down and be compliant or you put a stud in, drywall and move on to the next thing.

I'm sure when I tell my tenants about it they will be compliant and not do it again, they're decent high functioning people.