The cost is the same once you compare apples to apples to a traditional CMU or concrete wall.

The current list of concrete expenses are: Insurance, Trash, Water/Sewer, Electric/Gas, Tax, and Mortgage.

I am considered renovating the bare-bones, concrete-slab, water-intruding basement into a second unit.  

This terminology "double close", "simultaneous close", "wet close", "dry close", etc. is hardly cast in concrete.

I wanted to hit my head on concrete so many times when dealing with sac county permit dept.   

No business plan is ever cast in concrete.

I would first of all start by getting a Concrete Number of what the house is worth right now in the current condition.

Second what Marco Santarelli said, above - we're complete turnkey (including management and exit strategies, all done in-house) - and the vast majority of our clients are diversely hedged all over the world - they wouldn't dream of trying to manage anything themselves - they do bottom lines and executive calls, and are quite happy to remain in this position, entrusting the ongoing sourcing, facilitating and managing of deals to reliable contractors like ourselves.Takes all sorts, I don't think there are any concrete rules about who uses turnkey and why.

No concrete advice how to do this due diligence?  

I would put some rebar in it and fill with concrete.