The buyer definitely owns the property, otherwise it is not owner financing, it is some sort of lease or option or a combination of the two.

If you bought 5 properties with $300,0000, they all need to be throwing off a total combine of 20% return to get that $5,000 (as the example above shows), to get that expense coverage for your ability to leave your job. 

It might be a combination of stocks, bonds, mutual funds and alternative assets.  

in the SF peninsula and down to Cupertino there was a builder who built about 30k homes in the 50s and 60s  called Eickler these were modern heat in the floor tons of glass interior walk ways with gardens in them etc etc.. very unique ..

We have long term renters in Houston that are a 30 year old married couple, combined household income of about $110k, and they're going to be renters for 3-4 more years (based on their own admission).

If the other houses you own have no loans could you stack all their combined monthly rental income to pay off the remaining $120k mortgage before you retire? 

There are some out there that teach how to best use a combination of marketing types.

that short term loan - whether it's a HELOC or hard money or cash or a combination - has to be paid back regardless of what the end product appraises at. 

Notably, the leased properties are located outside the United States, and we manage them remotely.We have our downpayment saved and approximately $450,000 in combined equity from our existing properties.

I ended up using a combination of XL (each loan has it's own tab with loan details and amortization/payment table), Outlook Tasks/Reminders (to track upcoming due dates/maturity dates), and QuickBooks (for general ledger)...all held together with some bubble gum.