Unless Denver is different that most places that have source of income as a protected class, you have to accept S8 vouchers if the tenant has one, but you do not have to comply with the S8 program.Where I am, I'm forced to accept a tenant that has a S8 voucher, but because I can refuse to fill out the S8 paperwork, refuse to allow S8 to inspect the unit, and refuse to fix any issues any S8 inspection found, they will never actually issue a voucher for that unit. 

I have a source of private lending to place down payments on homes that I would intend on refinancing and repaying within 12-18 months.

One source of cities to avoid is Neighborhood Scout's 100 most dangerous cities.

Finally, a new Clark County ordinance was passed prohibiting property owners and managers from discriminating against prospective tenants based on the source of their income or an eviction related to a loss of income experienced because of the pandemic (section 8 included in the source of income discrimination).Nevada previously was a very landlord friendly state.

Calling it a cleaning fee (vs. revenue source) and treating it like a pass-through cost gave it the illusion of being a double-taxed service.

And also some options of a source of cash if we need it.

Here's a link for the source of the data. 

We flip in WA state where the market is hot and I have been challenging myself on what is good and what is over the top.if you spend time searching Amazon, clearance sections, Ikea, &  build relationships with vendors (my countertop Co) you can source current on trend finishes and not spend a ton. 

Or is it a MLM approach, providing a main source of income for the gurus/coaches to go fund their own deals?   

As long as you promote your properties for rent on the main channels, such as Zillow(One of the best, as it crawls quite a few sources), AZ Republic/AZ Central (Heavily read by many PHX residents), East Valley Tribune, Craigslist (inferior, due to scamming and lack of reach, but still works and free), etc, you will generate a lot of interest.