From other reading I've done, I know that many businesses feel there is an advantage to registering their LLC initially in Delaware or Nevada for purposes of helping to conceal ownership as well as Delaware's structure for handling business litigation matters. 

Since the structure does not touch the higher risk zone you should be in the clear. 

I would have structured to offer money to entitled seller pursuant to interloper using my expertise to 'give Bootsy the boot'.

My thinking is a good contractor, or an inspector, should be able to spot needed structural repairs, to make up his bid.

I'm trying to wrap my mind around how to structure it.

Just curious to know how others structure their own seller finance deals. 

Then take that info to a lender of your choice to establish the preliminary financing structure.

Structurally, horizontal cracks are more worrisome.

Most toilets structurally are the same, really.

If there are no comps then you would have to rely on quotes you get from General Building Contractors to give you a cost per square foot to build at that location But without actually building plans designed and stamped by an architect and structural engineer you may not be able to get exact figures but a ball park figure at best.