I typically ask about replacement dates of roof, electric box, plumbing and water heater).

Losing the step up is lot to ask of someone in the age range you are dealing with and holding fully depreciated property.

Your insurance policy should fit your needs, not the insurance carriers requirements.Look for a commercial insurance broker who can offer a wide range of insurance carriers.  

my guess would be water,sewer,taxes,insurance, maintenance, capital expenditures, common areas (everything but the principal +interest ) 

This range is reportedly not reason for alarm within an enclosed living area if no visible mold present.

Even though someone could theoretically purchase a note for $30K and just let whatever happens happen as they work it out, there's an inherent safety in spending the same $30K to just purchase education to help navigate those waters.

To connect our house to the apartment above our garage or "Additional Dwelling Unit (ADU) we had to have pipes excavated underground to ensure that the garage apartment could connect to sewer/water from our house.

They charge a loan renewal fee in the $400 range.

The offer sounds tempting since  the group has to finance about 3M$ (the rest comes from a bank with a low interest) and the building is bought about 1.5M below value, so when we sell we should expect a 50% return when selling which should be 3 years from now.The thing that bugs me is the way the building value was evaluated, i am copying a section from the presentation:"Market activity has shown similar properties consistently trading in the 4.75-5.25% cap range (refer to “Comparables” slide for specifics).

I don't give a flip about the student loans as they range from 2% to 7%.