This is 100% top advice to think about - each state (and sometimes, often municipality/city) will have different processes, rules and yields for this - it is a very location-specific strategy and have to hyper-focus on a local market (more even for the rules/process than the real estate knowledge) to have success

Two of them I tried to place them on Section 8, but they get rented before that happened.

We have a couple renting a house in Minnesota who is consistently behind on paying rent but they end up paying the full rent within the month, staying just out of reach of agreement termination.

You could also look into properties that have ADUs or do STR to increase rent.

Pé: Quote from @Braden Smith: I am located in New Orleans.

Stick to Local Property Locations: you should start out by only lending in areas you already have a good understanding of.

Locally here there is more of a lending appetite for build to rent housing than build for sale "spec" housing.

Renovated (mostly sweat equity) and rented with monthly cash flow of $570.

But the rents need to come in. 

The unit is coming up for rent again soon and I'm wondering if I am opening myself up for a claim of discrimination with this process - where a tenant who is not chosen could claim that I rented to someone else based on their (fill in the blank of protected class)?