I suspect maybe something like Hagerstown or Cumberland, which yeah are Class D like markets with declining populations, high drug problems, no strong job base which leads to non paying tenants.

The requirements describe the regulations in the Philadelphia Code.Landlords must follow all non-discrimination and housing laws.Renters Access Act tenant screening guidelinesYou must comply with this law when screening tenants.

I’ve heard from many (non-experts) that I’d need to stay for at least 5-7 years to avoid taking a significant financial hit, but that feels like a waking nightmare given how much this issue affects me.Financially, renting it out isn’t an easy solution either.

Assuming you purchased in your IRA for cash as most do, then there's nothing to deduct or depreciate because the income is non-taxable inside the IRA already.

For non payment of rent, follow your lease and retain an eviction attorney. 

Detroit is a market where local have a strong competitive advantage over non-locals so you want to use that to your advantage.

So trying non traded public REIT's and Crowdfunding. 

So many "investors" bury themselves in complex, expensive situations to protect themselves from some unknown threat to their non-existent business.Figure out if you have any shooting skills (or even enjoy the game) before spending money on $600 Nikes or an indoor basketball court. 

Next we will need to know if the non-conforming unit is legal.

In Philadelphia the fundamentals are strong: leading industries/employers are in the Education and Medical fields which are known to be stable, proximity to NYC and DC, national airport, port city, affordability compared to mid-atlantic predecessors.