At that point, I immediately submit my offer prior to an open house or any viewings.

Paying off the property immediately prior to a sale is not a problem. 

They would also provide title policy for lenders.

Or is there some sort of broad insurance policy for investors who often hire these handymen types. 

The purpose of those documents is that they establish the terms of the tenancy, that rent is paid, that there are no outstanding claims vs. the prior landlord, etc.

As a PM, I've dropped the ball on a couple things and my policy is to pay for my mistakes.

We learned from our mistakes on our previous post by having the property appraised prior to the renovation which brought back a value of 512k!

Second mistake: BOA and Chase bank both had policies they would not give me a re-finance for a mix-use property (I bought in cash).

I've used RentPrep for background checks (they do job history, credit, eviction, criminal search, call prior landlords, etc) for a few years and have been very pleased with their service. 

What is the best way to do due diligence prior to the auction?