On top of that you have idiots who engage in bid wars and pay retail for a house that has never been inspected (and those are the bidders who will cry foul when they discover totally trashed and destroyed house that will require a full gut job to rehab). 

Also you would not reduce the price because of the interest payment. that is not how it works.3. yes the note could be sold, but at what type of discount and what if the borrower stopped paying.while there are a lot of posts on seller financing, some estimiate less than 1% of all transaction have seller financing and the ones that do are first position only with an average of 30% down payment - most of these are to people who do not have verifiable income.Thinking you will get conventional financing then seller financing will be uphill battle as the conventional lender most likely will not approve a 2nd mortgage for purchase.not trying to dissuade you, just wanted to provide some key insights so you do not spend 1000 hours chasing something that is impossible to find.

He has been in the trenches in this market and has the battle scars to show for it.  

@Tyler EdmisterIf you are local and have the time to project manage a BRRRR thats about half the battle and it's what most people struggle with.

It's possible there's a bad smell or something like that making unmarketable? 

The smell of cat permeated the house and my mother said we had no mice in the house that year.Does the fact this mouse was found dead make a difference?

Plus looking to sell a property for her with over 100K equity after commissions, no capital gains tax .That new car smell with 6 miles.

And that wasn't even when it smelled the worse.

they probably have a bunch of 3% nonconforming loans on their balance sheet so 5.5% is not bad, totally reliable payments, plus in a legal battle they'd likely find the power of attorney didn't extend to the ridiculous term and that there was no breach of any enforceable agreement.   

Sure it can work for some but it is an uphill battle and like @Travis Timmons said, you are losing out on appreciation...the Holy Grail...I would just start buying property, some may work as STR, some may not....but they all should work as LTR.