Now for this to work I will need boots on the ground to go on appointments and put properties under contract.

Market seems to be saying your units are economically productive and on par with comparable units as is (based on tenants grabbing them).And, as you know now, that new smell and model home appearance of the totally remodeled and rehabbed unit will fade fast when the tenants treat it like, well, a rental...So you may just end up remodeling again if you sell or get a rough tenant..I tend to do more work on units prior to a sell and let the horses run with a rental with tenants in place that are relatively happy.

I am a real estate agent in Detroit, and myself and my partner will be the boots on the ground locally dealing with everything and also be contributing financially.

Comparing rent to similar homes in the area, you can be looking at anywhere from 675-1000$ per month in rent, depending on location, SQFT, etc.. 

For example some lipstick rehab compared to needs fully updated compared to gut rehab?

My goal (considering TVM principles) to get my money back within 5-10 years and for net present value to be better than selling and putting the cash in a conservative portfolio of stocks/bonds - which would be for me: 25% stocks/65% diversified bonds/10% cash or something of that nature yielding 3-4% after tax.My challenge still.... is the math and comparative analysis with different seller financing structuring. 

I remember reading the origination fees were much cheaper and more comparable to a HELOC and the rate was much less.

I'm being conservative with my ARV estimate, especially since there are few comparables, but it could potentially sell for 252K. 

No comparable house has been sold any sooner than 6 months ago but all close to the same age and distance.

@Derek Scott , I too think depends on the area and would be a good metric to watch when comparing houses that are close or in the same county.