And to tell you the truth, the low price sets off a few red flags to me.  

Luxury SFR segment is red hot, homes that were sitting for a year or more are all going pending and the ones closing are getting asking price.I also see the movement from equities.

Even if he has to show the seller your offer by law, he will advise the seller not to consider it without proper POF.Additionally, when POF is a given in transactions nowadays, not providing any POF raises so many red flags, the seller would literally be stupid to execute the contract.I think @Annie Bliss gave you the best advice so far if you really have a great deal.

The property is being sold somewhat below the average $ in that area (not sure if this is already a red flag), yet the rent disclosed in the posting is actually up to date with area rents.

I agree the prior listing would be a red flag; additionally, any good appraiser would not be 25% higher ($20,000/$80,000) based soley on a recent sale price. 

What kind of repairs would be considered red flags for wholesaling properties?

The whole beauty of real estate investing is that you make your kitchen table dreams a reality with simple business models (buy and rent for more than expenses; or buy and improve and sell, etc) not red tape, endless processes, and the complexity and frustrations you face (or try to escape) in your day job...Like Dawn says with the first baby, the perfect can be the enemy of the good.. probably some investors get too caught up with the analysis to try to be prefect when they could get a good deal done and manage it well enough (whereas the perfect deal person is still just analyzing and daydreaming).  

And even on the ones that do them, I think their lending decisions have a bit of a red flag mechanism where if they see you doing a bunch of cash out refi's, at some point, they're going to wonder if you're overleveraging yourself and taking all the equity out of the business.  

Areas with good price-to-rent ratios and high affordability are expected to outperform red-hot coastal markets in terms of price appreciation.Read more: http://www.crainscleveland.com/article/20150331/FR...

I'll give the book a quick red when I can, good luck!