Aside from going after E and O insurance and a formal complaint with the broker and real estate board, this is also good advice and another avenue to pursue.

Also, it is worth mentioning that we are near the Mexican border, which we have been importing materials from for other projects.

I would keep things formal like that with him unless you get married because things can go SERIOUSLY sideways.

Seller agents have an obligation "fiduciary" to their clients so they will have to show the home to unrepresented buyers, if agents want to try and cut the independent buyer out then they risk the buyer lodging formal complaints.

Nevertheless, consider reaching out to Borders and Borders for assistance with title work for more creative deals.

I’m an hour from the TX border.

Are you going to hire someone to make sure the corporate formalities are upheld?  

But I'd like something more formal and user-friendly for tenants and guests.

If they continue smoking despite the warning, you can then serve them a formal notice addressing the problem.

In the case of abandonment without something in writing, I typically recommend my clients go through the formal eviction process, especially when ANY personal property left behind.