While we newbies have you long-time experts on the line...Since the intent to fix and flip is a tax-intensive enterprise vs the intent to hold for rental and 1031 exchange, would it therefore generally make sense to buy your rental properties with post-tax non-retirement funds andinvest in fix-and-flips within an SD-IRA / Solo401k as long as all the work is hired out?

They do not advertise or seek to make loans.Issues can be in making subsequent loans, if there is an appearance of repetitious lending and it becomes more of a business operation than a casual loan or casual investor.

Subsequently, Morningstar decreased the value of these properties in their calculations by roughly $1 billion, from $1.5 billion in 2019 to $475 million today.

There is some controversy over what is considered property held for investment when immediately subsequent to the exchange, the property is transferred to a pass-through entity.

Refinancing isn't our goal-- though we have been able to cross collateralize properties that have appreciated as down payment for subsequent purchases.

The other thing I am considering just taking cash out refi on my primary home to pay for the rental property in full and then subsequently expensing the mortgage on the rental as it will be used to fund my rental.  

If you are serious about investing, all the education is there for free, and the biggest learning will be had on your 1st deal, and will continue with your subsequent deals.

Edited to say:The OP came back on a subsequent post to correct their understanding of what happened. 

Rucker in Enterprise, AL, which is my family member's desired area.

Our lease is very clear that a first violation results in a fine and a subsequent violation will result in being served notice to vacate.