And, if that guy doesn't have a home, the data is pretty clear that getting stable housing is the most efficient path with the best likelihood for a long term solution. 

“Smaller exchanges create a stable inventory of decent, affordable housing for working families.

I'd be curious to know why it hasn't sold in this market though, nearly every decent property is flying off the shelf, so I'd be a little cautious. 

Try to judge your market though; I agree with Veronica's point that the SFH may not be as stable due to demand but that's entirely dependent on your market.

If he has stable employment, makes enough money, good verifiable rental verification and no evictions, rent to them 

How stable is your income?

Cleveland and Columbus are a bit different but offers loads of opportunities.Columbus is know for its strong stable appreciation with slightly less cash flow while Cleveland is known for its strong cash flow but slightly less appreciation and a little bit rougher of neighborhoods.The most important thing is the local team wherever you choose.

That's a lot of volatility, I think of rent prices as somewhat 'durable' and stable for the most part with mostly low to middle single digit changes over time.

As for the screening, tenant is younger and has no credit history, stable income or rental references. 

This would put you in a position to best place yourself in a financially stable place as you save for the duplex and also build back strong savings.