Then once you actually have a deal under contract, invite that contractor out during your inspection window to give you a more formal estimate. 

I would send them a formal letter letting this know of this and start the vacancy process from there. 

Most of the 'piercing the shield' info I've found seems to be specific to cases where one has signed a formal contract.

I have a top applicant in mind already based on our phone conversation, as long as everything checks out with the formal application and credit check. 

Notice of Default (NOD): To initiate a non-judicial foreclosure proceeding involving a public sale of the real property securing the deed of trust.

Because the architect has no formal contract with the contractor during construction admin it is their sole responsibility to protect the client and make sure the finished product is of high quality (for the budget).

Fortunately there is light at the end of the tunnel.Lastly, Ive said it before, but you CAN do some level of screening while in the due-diligence phase (at least in PA) using the PA Judicial search (google that).

If a tenant is not paying rent or are violating some other term of their lease, you would need to deliver a formal notice and start the eviction proceedings (5 day notice pay or quit, 5 day notice health/safety, 10 day notice of material non compliance).

New York is a Judicial Foreclosure State which means the mortgage holder must sue the mortgage holder and receive a judgement from the court which I assume is public information. 

I'm new to the REI world, but have always been interested in real estate in some form or fashion while working on my formal education and looking to jump into the Rat Race (ha!).