I can refer several PM solutions for both long and short term. 

I'm curious if there is a simpler solution. 

The owner/occupant has a bit of financial trouble.I would like a solution that allows the current owner/occupant to stay in place, but also secures the property for our future use.I've considered purchasing it and offering lifetime in exchange for rental payments equivalent to property taxes, insurance, and a maintenance allowance. 

While the rates are higher (8-10% or 4-5% over the lowest cost conventional debt), it can be a good bridge/shorter term solution.

That is close, and might work on a case by case basis, but is not a real solution.

You'll be surprised how fast the tenant stops contacting you with outrageous requests when they know it will either cost them $20 an hour, or they can search for the solution online for 10 minutes.

Because it's the only solution we can come up with in markets where there is a massive division of wealth and property is scarce?

I'm really looking for the solution that will add the most value to the duplex but also last a long time before I have to worry about the floors again.

Together you and your partner need to come to a solution.

Expansion of Section 8, tax deduction for rent, change in zoning laws, higher density housing etc are all better solutions than rent control.