Very likely the seller doesn't know the income-producing value of those extra spaces and therefore has not included it in their pricing.

If you have a lot of equity in your home I would first evaluate if it's possible to leverage any of that equity to acquire another asset that would produce more cash using a home equity loan or line of credit3.

You may see a difference if you're selling to an investor that would price it as an income producing property. 

If $23k is just a “hope and a prayer” then he’s going to have a very hard time producing any CREDIBLE itemized bill.  

I am looking for a house inspector who goes into every tiny details that need attention and uses a good reporting tool to look at the issues.

I would highly recommend you sell and do a 1031 exchange into something that will produce income, like a rental property.

If it is way more work and maintenance but cash flowing the same as a smaller unit doesn't make sense, but since you say high maintenance high reward I'm guessing this is one of the best producing properties.  

The C areas that produce the most cash flow are Linden, Whitehall, and Hilltop.

The thing I've found with tiny houses is that the outdoor space has to be amazing (design and view-wise), or it struggles.

They'll produce a title commitment with the requirements they think are necessary to get you insurable title.