They decided to pass on the house, and are under contract on a different house with a normal layout and a garage.

Also I know there are different Class Areas and that I should avoid anything that’s in Class D area.

Even insurance is a variable since there are difference in carriers, risk profiles, and portfolio size. 

They are hoping to sell this land to purchase different land and would like to eliminate a taxable event.

Businesses goal is profit and in the form of STVRs it is net cash flow.A STVR building/ home is not much different than a business like Walgreens triple net leasing a building.

You can try to negotiate something different after the sale, but the tenant must agree.

Im actually just finishing up on an ADU down the road at a different property so that may be a good indication if I can finish it quick enough to see resultsI also was thinking of making the barn a combination of both and make it like a bar themed loft for a guys / bachelor trip and build the simulator in with the living room as it can double as a projector type screen for netflix ect. 

Areas are different obviously but I'm just looking for opinions before I make the move.

Their initial setup is quite a bit different from Stessa.

Definitely depends on lots of factors - I would strongly suggest learning how to do basic modeling/underwriting and projecting the cash flows out in different scenarios