You need to read your docs and get very familiar with them and note any discrepancies between what is written and what their "common practice" is.

I was approved for a HELOC but the discrepancy between the flood zone stopped it.

Rent roll, P&L 12 months AND year to date (sometimes it looks different you want to find discrepancies if any).

We are ready to make an offer on a beautiful college town rental that has been recently rehabbed, is now turn-key ready, and all the numbers really check out for this to cash flow well. 

There is one major dilemma:...

We also noticed a discrepancy in the city listing that seems to rank the value of the property lower than it should...in other words, there’s a city rating that shows blocks of properties and assigns a square meter value to each block.

What accounts for this discrepancy? 

Wholesaling as a strategy is really just about understanding the discrepancies in market values. 

The bigger the discrepancy the more I would consider trying to get them out- Are they actually paying the rent the landlord states currently?

Market changes or you have credit discrepancy such as a late payment, high DTI, excessive trade lines (High risk) multiple mortgages and high revolving balances over a certain percent the bank has the right to reduce or close that account. 

You may uncover additional discrepancies.