I even called a city inspector who had been through the house and got an idea of internal condition. 

That said, "chickens coming home to roost" from the various seller-financing deals done WRONG is a very strong potentiality, as issues of such will most likely grow in occurrence and thus possibly press internal audit's that uncover such, and resulting enforcement actions start enacting in a volume.

That always makes it so much harder to rent, or secure a great tenant.Here's my standard go to list now for long term rental updates:-LVP that looks like wide plank white oak-Ultra Pure white on all the walls-Vertical/ modern stack backsplashes and showers-Pop of color on the cabinets (pop of color can include black too)-Butcher block countertops (lower end) or white quartz countertops (higher end)-Modern light fixtures in brushed brassKeep it neutral still but a couple of style choices with the light fixtures (which are cheap) and it will appeal to the masses.Good luck! 

Its standard builder grade that I believe most people are sick of. 

Remember that books are going to be out of date to the market standard pretty much right after they publish. 

My business partner and I have a joint LLC (shared business bank accounts / credit cards / etc) - pretty standard stuff.

But, for instance, someone who has lost their job, probates, someone who has been transferred, needs an immediate sale, it's been a long time on the MLS but hasn't sold, plus properties not up to MLS standards so they won’t list well on the MLS, and other of "life's occurrences" are all reasons some people sell on subject to.

A third party likely purchased that debt from the original lender (uncollectible by typical debt collector standards) for pennies on the dollar. 

Can anyone point me to the best US based resource either private or commercial that does loans for international real estate purchases?

What about good Standard Operating Procedures (SOPs) to make it easily repeatable?