What would I need to do to structure the note in order to have a note buyer come in and buy the note or buy a partial enough to pay off the 215k at closing and still have some difference coming to me or the note revert back to me after the partial was paid for. 

The struggle comes when you plan to sell, pay close attention to how the bank would treat the loan in the event you would sell.Even though its a bit more work, banks are typically open to these loans as it provides them with additional collateral in the event of default.  

HCV in the area pays $2,200.

That means paying all cash isn’t an option unless you plan to bring another $600k to the table. . 

Not to mention, the right system will enable your tenants to pay rent online, have a tenant portal, and all the other features that both tenants and owners need this day and age. 

Then there you go.One thing I am looking to try to do but haven't done yet is buy something with zero down on seller finance, put the rehab on a 0% credit card, then refi the seller off in 12 months and pay back the card. 

Owning a duplex at 20 is a huge accomplishment, and it’s inspiring to see you’re already planning your next move.From my perspective, real estate investing is a long-term game focused on building equity, paying down debt, and maintaining stability over chasing short-term cash flow.

Quote from @Chris Pontello: Hi Chris,Correct me if I'm wrong as I'm still learning creative financing solutions, but paying them some money would be if I could take over the loan.

Example, a short pay history - non-redeeming factor, a 25% down payment, a redeeming factor to counter the short pay history.

Now, you need to figure out how to find deals and pay for them.