I'm a licensed contractor in NYC and I have a good friend who's family owns a property here in Crown Heights Brooklyn that’s basically all paid off and taxes are up to date.

Are these areas good for rental property investments, or am I barking up the wrong tree? 

It depends on your financial strength, the quality of the property, how many properties you own, etc.I like to start with one significant expense and three months of vacancy.

For co-living spaces, it’s important to confirm that lenders are comfortable with the unique rental model, as it can impact property valuation.

I just checked all my properties and they are still showing up in chronological order.

Quote from @Maxwell Servais: I have a tenant in my 4-unit property saying that hot water runs out after about 10 minutes.

Since acquiring a four-unit property on the Northwest side, my bi-monthly bill has typically been around $500.

I am currently looking into private lending on another property in either Illinois or St.

Where is the property located.assuming the seller added the ADU and did not disclose the ADU in disclosure forms, you may have recourse (depending on the rules of your jurisdiction) but it may cost you some legal fees. 

We each pay $300/month (allegedly) and there is zero upkeep to the property (no pool, landscaping, common area).