this is the distinct different between being an actual lender like a bank .. and an investor in a fund.. two very separate transactions.. when you lend and receive collateral on the asset you get paid when it pays off or the borrower refinances etc. 

What they said.....everyone over the age of 18 has to have a background/credit/ ID verification and sign the lease.

The IRS is very clear about the distinction between the two scenarios.  1099 subcontractors provide their own tools, set their own schedules are not directed by the hour. 

We focus on layouts that feel spacious but still define distinct areas for living, dining, and entertaining.Flow is Everything: A home’s design should feel seamless.

Based on the knowledge and experience you have, would you consider this strategy if you had to go back at my age?

Second, the ownership of the relinquished property and the replacement property in the three (3) Private Letter Rulings involved two distinctly different taxpayers.

Property values continue to grow in value, and you can actually live off the rental income.I think it's best to hav all properties paid off by retirement age, since that's when you are going to rely on cash flow for your living expenses.

With that in mind, I’m considering purchasing four rental units over the next four years to build a stream of income that could help supplement my retirement by age 68.The challenge I’m facing is that the deals I’ve come across so far don’t make financial sense.

Age is relative. 

A formal business built on this seems overkill as you’re essentially paying someone for a service that already has standard model.If you and the parnter have distinct business tasks/abilities (i.e. not what you would hire an agent or contractor for), such as off-market lead generation, that’s a different discussion.