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?

The village the house is located in requires an occupancy inspection prior to sale, when the inspector viewed the property, they issued a non-occupancy permit for me to sell the property, but they also want me or the next buyer to pay for 3 permits and fines for work not done without a permit totaling 1k.Several investors talked with the village inspector and they reportedly will work with the next owner to resolve the permit issues without forcing them to tear out the existing work.

Turns out he blew out the attic 20 years ago and added the 5th unit there for a prior owner. 

The redemption price tag is the same as explained in my prior answer, and starts with the $15,000 winning auction bid. 

Put out a policy with my tenants if you break something you pay for it.

On April 16 I was notified that I needed to install hand rails on the front steps or they would cancel the policy.

Or you could pump prior to occupancy and if you really want to charge it make it a pass thru.

@Chris ReevesOne of the great advantages of syndication is that it usually exposes an investor to a class of real estate they had no access to prior.

Then make sure to have the funds in the account 2 months prior to looking for a property and getting it in contract.