These numbers will never be big enough to change the whole picture. 

The relatives are vacating. only 1 tenant wants to stay through ownership change.

Hopefully you won't ever have to go through the eviction process in NYC. 

Whomever will do her taxes when she does sell, (can be done prior, and should be asap) will have to submit a change of accounting method form .....I've had multiple clients that never took depreciation and when they sold, we had to fix it...doing your own taxes isn't as easy as some tax software companies make it seem 

Ultimately it's less of a science than an art, but people rarely truly change so what they did is probably what they'll do.

So I look at it from a monthly cost basis - taxes change as years go but for now this is what the deal is.  

If you ever have any questions or need guidance, feel free to reach out.

Quote from @Chris Seveney: Quote from @Eric Henson: Do you guys ever take the risk of buying a foreclosure at sheriff sale with the previous owner still living in it?

They need to transfer the tenants' deposit to you (or your new PM) and let the tenants know that there is a change in management. 

But because market prices of properties went up like crazy and so did the market rents, both tenant and landlords are not cognizant of the changes.