I figure my credit card statement retains the transaction amount, so I figure that will cover me. 

@DrewSing took me out to Thai Food one time, he recently bought a 5 bedroom fixer in Washington, and the rest is history.

Clearly you will need to raise the $500k privately given your current credit situation.

Assuming you have equity and you qualify for a conventional Fannie/Freddie loan then yes you can.You should also call the small local banks and credit unions in your area as they can be more competitive.

He wants to pay for the whole year rent if his credit report comes back blank.

It might not be them, it might be family, ask for two years of employment history (Income) and the last two years of renter history (Trustworthiness).

This is in NJ.I spoke to someone from Andrews Credit Union who is offering 95% LTV HELOC but the banker is unsure if the underwriter will accept a duplex.

Once the now performing, modified note has a 12-24 month payment history, the note holder should have an asset with a significant capital gain.Note secured by commercial property carry rather light regulatory baggage.  

I have good credit 750+.Thanks for the help!!

Is this the best way to use funds to appeal to more buyers, or leave it as is and offer credit.