I can see how investors would disagree, but overall concept: you get what you pay for

It could have the unintended added benefit of proof-of-concept to show buy & hold investors, and in the end drive additional development business. 

Neither do you have depreciation, 1031 exchanges and a lot of other concepts.

Either way, I would try and come to a compromise if it is a property that checks the boxes for you, because I know in my market in Connecticut it is very rare to find a seller that will even entertain seller financing primarily because they can't grasp the concept and/or they need the money from the sale. 

It’s an amazing concept.

I got rid of my retirement funds and 401k a few years back after I had proof of concept with 11 turnkey rentals.

I think you have the concept correct.

I am new to BP, but am familiar with a lot of the concepts here (FI/FIRE, BRRRR, 1% rule, house hacking, wholesaling, 70% rule, etc).

I would think about the IRA withdrawal and this deal as separate concepts.

The concept of NPV and discounting cash flows makes sense to me.