This will vary based on foundation type and cost and ALL finishes- interior and exterior. 

If they don't have documented income or so, you're out of luck.

That is a type of commercial insurance and not a simple homeowners policy.Regarding the little things, yes that is what AirCover is for.

I would suggest looking at Furnished Finder (https://www.furnishedfinder.com/housing/New-York/New-York) to see what type of MTRs are listed in you area as well as Airbnb and VRBO for 30+ day stays.

This is the "hard" part of RE investing - finding a market and property type where the #'s will work favorably.

The assessed values are your supporting documents. 

Purchase price: $3,000,000 Cash invested: $500,000 this was a value add deal What made you interested in investing in this type of deal?

When you see an e-signature on a document, all you see is the signature and maybe a date/time stamp.

My advice in this type of question is to consult with a real estate professional or financial advisor can also help you make informed choices about investing in that particular area.

Since you will be at the property doing the majority of the work, I would hire multiple professionals for the different types of work.