Also if he is just taking PITI into the equation, he is missing/withholding info about utility costs, stocking/supply costs, cleaning costs, etc. 

I’m a Superhost on that- we have people on the ground with maintenance, cleaning, security is fantastic .

The classic one was Tenant leaving huge amounts of grease in kitchen, inspector requires landlord to clean it up.2) Tenant vacates the unit without notice early in the month.

When you say swap out carpet - do you mean ripping off the carpet and replacing with laminate flooring or something else?

Houses have flipped on my street for $MM - bought at 400k and sold at 1.7M or bought at 800k and sold for 3.2M, etc...We can either add a second floor and invest a lot (OPM) and sell or invest a little (our equity) not add a 2nd floor and rent it out to keep it for future sake.

This test ensured that 75% of the total monthly rent for the building would cover the mortgage, taxes, and insurance on the property.For example, consider a three-family property generating $2,000 per floor, totaling $6,000 in rent.

I stay away from historical buildings in general for all of the above reasons and more, unless it's a larger scale commercial building with concrete floors and great "bones" that can separate the uses/tenants better.

My lease is written such that an unauthorized pet has associated a per day fine of $50/day (which is about what pet boarding costs) plus for any animal stay tenant agrees to HVAC duct cleaning and professional floor cleaning to remove any pet dander (some people are very allergic to pet dander).   

How does one go about obtaining a basic floor plan of their AirBNB to submit to the city/county?

You can read for yourself here: https://www.clevelandheights.gov/205/Point-of-Sale-Inspectio....If I understand correctly, they must disclose it before they can accept your offer and they should make the required repairs before they can sell the home so that you have a clean Certificate of Compliance.