Q&A 9 was never finalized as previously written, and is now Section X "Amount 2" in the 2022 reissue of the Interagency Guidance, which does not prohibit applying demolition cost (or any cost to that matter) to non-farming, ranching or industrial purpose structures.
If the building would not be replaced if damaged and the appraiser and bank agrees it has no value relative to collateral, then determining a demo value and insuring to that amount (if it simply can't be demo'ed today) seems a very reasonable, sensible, and easy to document solution.
My opinion - take it or leave it!