They are not the same thing, but if the building was constructed prior to 1969 without undergoing a change in occupancy type and no major renovation permits pulled, it will likely not have or require a CO.

I keep constant reserve of 3% for major improvements.

What are your thoughts on managing the first property yourself and just purchasing a home warranty for the major repairs?

The majority of Airbnb rentals are not in prime locations like that, and I doubt if they bring in nearly that much of a return.

Clearly big things can pop up but to begin I will not be seeking major rehabs aside from floors, paint and rehab of bath and kitchen. 

I would keep it at 10% ($528.60) until you have the property inspected to determine the current condition and life expectancy of all major components and appliances.  

Currently, they are living in the house, with three other roommates that cover the majority of the mortgage. 

If you plan on a major HVAC upgrade you might need to deal with the asbestos.

I'm here to tell you and give you info that the minority of real estate investors are doing, not the majority.

These expenses have a major impact on the cash on cash return.