If you find an area where houses are getting lots of contacts and applications and you see the rent prices could work with the purchase price and the ownership costs you probably have a good area to dig deeper into.Last thing to mention -make sure to check if it is in a flood zone, as flood insurance would be an added cost, and make sure to check if there is a MUD tax, as that can be an added cost as well. 

Had a guy working on my foundation, said there's plenty of areas where if you were doing push piers for fixing a foundation you would never hit bedrock, no matter how many you used, just mud.

The mud rust and dedication back up out the sinks and laundry drains.

Realistically, to buy a detached property with a basement suite that is in somewhat decent condition, and not in an undesirable part of the city, you're looking at a price point starting in the low 500s (520K-ish and upwards of $650K for turnkey renovated older properties with legal suites).

Your expenses are going to be basically fixed, and the only way rents are (probably) going to decrease in the greater NYC area is due to a lot of new supply, or some big economic event/natural catastrophe/terrorism etc. that makes living in or around NYC suddenly undesirable.

As a former contractor myself, in my opinion it's no different than your average home owner trying to frame a wall or mud sheetrock with no experience, it's going to be obvious in the finished product to anyone who knows what they're looking at.

There is software you can get to determine square footage, number of residents, etc and bill each one individually but then you're paying the bill and a month later you're billing the tenant but keeping it separate from rent and it's a real pain plus this is very undesirable to tenants.

Clear as mud, no?

I did like that the broker expressed they would not drag my credit through the mud trying to find lenders. 

House hacking in California with 100K budget in a more undesirable area maybe your best bet if you decided to invest in California.