. - I would try to set the tone early that you're firm, but fair.  

You could have a lawyer review it, or tone it down to only include the doctor note.  

If that's cost prohibitive, paint the vinyl kitchen floor with tones from the slate.

I think you are going to need to describe your concept in much more detail. 

If your "gut" is to be extensive enough to need to remove the electrical entrance for an extended period, you can have the entrance moved to a temporary mast on the property ... perhaps even with an panel (may need to be sheltered to comply with local code) to provide electricity on-site.The other alternatives are to 'pay a neighbour' to be able to run a few extension cords from their property or use a generator.

Better by letters or maybe even email.Also, be sure to keep all emotions out of your tone and responses.

You're going to need several years of operating reports to justify a new, higher value.  

When you start comparing properties, you're going to need to adjust prices to compensate for differences.  

Since this is the first time they have been late, your response sets the tone for the rest of the lease period.

I think as you learn more about note investing and become more familiar with the moving pieces, the segment you once found negative in tone becomes informative and loses tone altogether.