Income way more important than credit. 

Congratulations on getting yourself to the point where you know you want to invest in Real Estate - and also with a good amount of cash on hand for someone only 20 years old.Depending on your credit and job history, you could qualify for other type of loan programs, too.

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

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.

Some of the worst renters I had complained about everything and had no respect for the property, while some of my best renters were a day or two late on the rent but were cooperative with upkeep of the property.

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.

when we would log over a timber track sell the track to a new owner who was looking to build but needed a year or two to get permitted house sold  etc etc but would buy from us on terms then we hypothecate the note.. but we owned the dirt free and clear .. and to do this you needed stellar credit and balance sheet .. banks were just not going to make loans because you had a note  LOL.. 

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