A few caveats - 1. wether permitted or not, if you're renting the basement of your SFR you really need to be judicious about who you rent to.  

It would be interesting to formally find out but they own decent chunks of some of the most valuable stuff in Cali for sure. 

Many owners do not run their apartments like a {formal} business and, sadly, what you have encountered is very common.Your broker is steering you in the right direction.  

It may be possible to avoid a formal probate and the ensuing delays. 

They would like a 50% deposit.The guy I'm dealing with is clearly not from here, although he can speak English well enough, he can't write very well and they don't have a formal contract though they are willing to sign one I put together.

a) what kind of company {dba, llc,corp}b) research company reputation, licensec) get a formal request from the CO with a commitment that the CO is a CO-SIGNER, co-leaseed) the applicant guarantees the lease.

Probably 100 books or so and the best bang for my buck has easily been BP membership and Local Real Estate Investment Association dues.Compare that with the $250,000 I spent on "formal Education".......

Once owned, the visit would more be for the purpose of submitting a formal proposal. 

I hate formal partnerships or IRS Employees w-2, think HEALTH INSURANCE!).

Any of these will not float if the borrower objects and seeks a judicial route.