Also, it's still a small percentage of owners that have floating rate debt.

These are really questions for your attorney - the more typical scenario for a jv like this is you have a new LLC where you are the manager of the LLC and the investor also owns a percentage of it.that way you don't have to deal with transferring it etc. 

This implies as a percentage of rent the maintenance/cap ex is higher at cheap rent points.

This is invaluable because there are so many variables and questions you will have if you don't want to lose money.  

I know what the rents should be for each of the units (2 vacant and 1 significantly under market), the taxes are listed on the MLS, I’m familiar with the water/sewer costs in close proximity to this building, and I know what percentage to use for my Vacancy, CapEx, and repairs and maintenance based on my knowledge of the local market.

Meaning higher percentage means less of the 70k I would need to put down for the new house?

Based on your age & needs, you could consider a variable annuity (stock market) vs a fixed or deferred annuity (more like a long term CD). 

Median-priced homes will attract the highest percentage of qualified residents looking for rentals and the highest percentage of owner-occupied home buyers in the future. 

It's everyone who realizes they are not capable.And the percentage of folks capable is minute, very minute.

I think if the end result is affordable housing people need to be invested in their own housing otherwise a good percentage of the beneficiaries of your program won't care.