It seems like you have it all lined out already, timeline and all.

I have some buy and hold rentals and have never done a BRRRR.

It's good to see it through each season then you;ll have a better idea of what to expect. 

i guess the moral of this story is: in any endeavor you must take action or nothing will happen!!  

So if you are looking to hold long term, you must take that into consideration.

I don’t know of any camps of people more entrenched than the “cash flow is all that matters” and the “you must use leverage” people. 

Yes you have to be able to afford to keep the property.

Often times you will pay much more in taxes than if you pulled the money out, paid the taxes and penalty and then started investing in real estate.For example, with the financing you mentioned, the IRA must pay taxes on the portion of the profit earned by financing. 

I have done it successfully on my last 2 buildouts, maybe 3, but only because I was able to acquire the properties at a very low price and I did all the work in-house (myself and some hired hands on staff).

To qualify for installment sale you must selling an investment property, it was a rental for at least a short period.