I only needed to verify them and generally their conclusions, but there was no sense in reinventing the wheel from scratch. 

To what extent should I be verifying that they have the correct licensing? 

I've requested a ledger from the owner to verify the tenant's payment history, but I'm aware that documents and screenshots can be falsified.

Most out of state investors are looking for markets that are basically identical to the Detroit market.

To get 'over' 80% LTV they had to verify 6 most PITI reserves (as opposed to 3 months). 

Whatever it is that you mean by "borrow over it", it will be true with Whole Life or IUL.It's important to understand that under the Hood, Whole Life and IUL are virtually identical.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

I am currently reviewing the numbers associated with a wraparound mortgage and I need some assistance in determining if they make sense.Can anyone please direct me to the appropriate person who would be able to help me analyze and verify these figures?

Landlord tenant law has its own version of ambulance chasers that would love nothing more than to make a few bucks off of a landlord that tried to read further into a tenants life than just criminal history, verifiable income, credit score, and rental history.Logically, we would all like to be able to make decisions based on personality differences, family size, possible income drops, or whatever gut feeling we have.

I would recommend getting some trustworthy eyeballs on the property to verify that the issues coming up are valid and the costs are in line.