If I calculate my actual cap rate after 6 months by using their convention (Subtracting insurance, tax, property management from gross income) numbers match, thus I am getting what was promised on my proposal.

I am looking to find the optimal tax and legal structure to optimize his situation.

If you’re going conventional on a second home, you might want to consider putting even more down and make sure that your debt to income ratio is <41%, and credit at or above 780, ideally, as the GSE’s just made changes to the Loan Level Pricing Adjustment (LLPA) just got even more expensive effective 05.01.2023 but most lenders will either incorporate this into their pricing or will then. 

But, most retail, office and industrial leases are, at least partially, NNN, so when your tax bill goes up, that is on the tenants.  

At this point, i don't mind going with the debt collectors after the judgment.

Once you have a tax deed and the redemption period is over and you have advertised the foreclosure, it would be a good thing to do a quiet title and an official closing with a title company or lawyer so you have no outstanding debt or surprises on the property you now own.  

Will one or both partners guarantee the debt?

I secured a 250k physician loan (no money down) at 7%, which brings payments to 1707/month, and 1887 with insurance and taxes.

My name is Vladimir, my wife and I are Ukrainian refugees residing in Canada (I have russian passport and my wife has Ukrainian one), and we are looking for a ways to invest in tax deeds in USA.1.

Same goes for number of LLCs and what to fund them with, since bear in mind that CA tends to be more cumbersome and expensive to have LLCs than other states.California is generally more cumbersome than other states when it comes to taxes and filings.