I then declined due to income and credit; which is still an area where we can decline.

  Hitting up on Grandma or maxing out the credit cards as the scammers advise gets old to hear. 

Replacing old carriage beams with new ones (which are straight) is a bad idea, as it will force the whole house to straighten out (and crack the plaster).

Of course run their credit.

The cost of the rehab is ~$250,000 with estimated ARV of $1,200,000 and the total rent at $13,000, which would generate good cash flow.I make $100k, have really good credit score and ~$100k in savings.

They're targeting credit card companies, banks, hotels, airlines, utility providers, food delivery service, restaurants, auto dealers, event ticketing companies, and last but not least, property management companies.

What is the good, bad and ugly of this? 

But that can be a real problem unless you get a Title Report before you buy.As bad as not knowing how clear the title is, you also don't know the condition of the property or now as a growing problem, whether there are squatters occupying it.  

Purchase price: $915,000 VA purchase, sfh, 1st floor fully remodeled for sale, incentives in purchase - 15k cash credit (paid warranty policy, outstanding HELOC, loan fees).

Not a bad way to start, but if you can look for more efficient ways to close deals, that would be better.