As others have stated above, there is no difference for federal income tax purposes.That being said, your business structure should not be influenced solely by tax implications.  

first some background:I'm buy a property with two duplex, one of them has structural damage and I am going to tear it down.

It's completely open and has support beams holding the structure up.

Build a network of wholesellers, RE agents, attorneys, etc. that may have access to deals and would bring them to you 1st based on your relationship and incentive structure.

If you want a tie-breaker,  you can hire a structural engineer for around $400 - they will give you a clear statement as to what is needed.Also, be sure to consider the age of the house and where you are lifting e.g. near a bath, kitchen or other potential drain line) - if it is an older house and has cast iron pipes, you will probably have some plumbing work when you are done lifting. 

They just ensure you sent the necessary paperwork to document the transaction.A Checkbook IRA LLC is an enhancement on this structure, and makes sense if you will have a decent amount of interaction with the investments, as is generally the case with rental property.  

I'm OK if they make an educated decision not to go that route ... what I try to avoid is the seller not fully understanding the structure of the deal.

I've asked around about owner financing and there have been a of of no's and then bad deal structures.  

The property has structural defects10.

Structural repairs, lead paint abatement, high tenant turnover.....