Is the tenant responsible for all interior and exterior pest problems or is it strictly interior?

Depending on the purpse of the BPO and regulations in your state, you can just call a broker that you like and have them give you a BPO. 

There's a limit to how much repairs can cost vs. a complete raze and re-build(will check current regulations to see what they are).My only concern are the liens and the problems inside.

I keep telling my fellow US investors how spoiled the are every time they start complaining about something (taxes, fees, regulations, rent, compliance, etc.) in the USA market ;-) Try making it in Europe and you'll need to toughen up by bringing along more time, patience and expect less yield.

Generally speaking, per the NYC Zoning regulations, a R4B is limited to a maximum of 2-family homes.

We have seen a general drop an overall short term rentals mainly due to regulation.

Purpose of the Leasing Management Program The primary purpose of the Leasing Management Program is to regulate and monitor leasing activities within the community. 

Great input, @Greg Scott and thanks for linking those articles.I honestly hadn't even considered HELOC interest deductions, and it's not surprising that the IRS & banks have strict guidelines around this to protect themselves. 

In other words, these sources claim that you can't buy a property solely for investment purposes (like renting it out) without living in it yourself.Is anyone familiar with this law or regulation?

Start up cost have strict rules too.