With the profit I made from my flips I was able to put 20% down and do enough work to the home to gain around 60k in equity  but now I still have a small list of things I would like to do to the home and would like to have money for a down payment on a duplex .  

For example, you might own 4 properties with a sum total of 50k in equity but one of the properties generates $900 per month positive cash flow.

If you are building in $50,000 in equity that would take you over a decade to get.  

They scale a lot better, can increase in equity and cash flow pretty easily, and then you can get into another one.

I have about 18k in liquid-able assets and about 10k inequity in a rental property that I own in California, all of these funds I am willing to use. 

We have no debt except our rental property, even our residence is paid off with about $150K in equity.

My calculations show there to be $170,000 in equity after five years and $47,000 in vacancy, management, and capex.

Yes, you’d have $30K in equity with $30K down payment.

As a result, they hand over $50K in equity and their property, for zero down and $5K payable over XX months/years.

While I personally hold a bias the other way (thanks @JD Martin for calling me out here) in that I think "broke is a choice" the middle ground is that there is a portion of our society that creates inequal opportunity for all parties and it's harder for some people to succeed than it is for others (social mobility).