The seller requires a cash purchase & I’m exploring creative ways to structure the deal.

I recently joined the forum and would like to quickly list my requirements without much ado.1.

As for income verification, I require the applicants two most recent paystubs and if self employed I need their most recent tax return.

Then add any other codes required where you want to build and study those as well.

You can put a mortgage into a "trust: without triggering a due on sale but again contacting your bank/lender is the best route to avoid any issues.Some banks/lenders or servicing companies change guidelines and even a trust may require other paperwork but the attorney usually facilitates that to be safe.  

So I require skin in the game (average is 5% to 15%) to offset this.

If they sell them on amazon, they likely don't require any special handling.

As Jonathan mentioned it can be done, but they may require an appraisal of the property. 

I understand I cannot legally require them to respond, unless the notice specifically requires it, like for instance, a notice of entry, but it's making it difficult to manage the property, and I'm not sure how to proceed.

What special purpose equipment do you have for an ADU/Office that required unique wiring for it to function?