@Nicholas Moran Zillow publishes a statement regarding the accuracy of Zestimates here: https://www.zillow.com/zestimate/#accHere in the metro Boston market, they claim to be within 10% of the sale price 78.1% of the time. 

Caveat: NY laws changed recently, so you might double-check the accuracy of the info here.Good luck!

You mentioned a VA loan and this is a really large property.I can't comment about the numbers accuracy as I am in South Carolina, but I would consider a a smaller property. 5 bed, 3000 sq feet, and $2500/ month all limit the tenant pull. 

It would be really difficult to get sound advice without consulting a civil engineer in depth about both the subdivision and permitting a new building on the land, they could run you through the process and costs with some level of accuracy. 

I submit both to my skip trace provider, as they say that improves accuracy.

Then for someone to clean up the data and double check for accuracy, errors, and skip trace more information on the representatives (Fiver or the like is good sources.) 

4) How do you warrant the accuracy of the representations?

I was looking on realtytrac.com for foreclosures and metrics in my area.  I tapped on the crime stats and the crime stats listed were for a city that was NOT our city but instead a city that has a notoriiously high cr...

Can't vouch for it's accuracy, but I use it as an indicator.If you haven't started already, do a lot of reading right here on BP.

Among them are:-Credit Score-Derogatory Items-Inquiries-Credit Maturity-Credit Diversity-Credit Report Aliases, Addresses, Employment Accuracy-D&B Score-Experian Business Score-Equifax Business Score-Revenue Documentation-Assets and Liabilities / Net Worth-Debt Coverage Ratio-Revolving Debt Ratio-Time In Business-Type Of Business (Real Estate is a red flag for many banks...you need to find the right one)-Secretary of State Validation-Phone/Voicemail Verification-Address/Phone Directory Verification-Website, Email-Bank Theatrics (How you perform on the phone)Are you looking for a specific type of financing or a bank that is flexible and will loan on different types of projects?