You normally do not have a fiduciary relationship with the listing agent, so what your observing might be both ethical and legal.

My partner and I researched a number of cities throughout the nation using info from sites like the bureau of labor statistics (https://www.bls.gov/) to observe population growth, labor force growth, median income, rent affordability, etc.

I observe that they can be quite versatile and cheaper than conventional housing.

If I was the Listing Agent for the home, my prime objectives were to observe the visitors reaction to how the home looked and their thoughts on the price.    

Tax implications would be a big factor, as would the predetermined buyout(or methodology for calculating future buyout amount), but the big factor would be their desire to max out profits weighted against their desired quality of life.But those deals are almost always a result of being observant at the right place and time.

When you get up to about 30 units you can afford a property manager.Home auctions can be OK but go to the first one or two just an observer to see how it works and you might get acquainted with some of the others that show up and network with them. 

Is this a correct observation, or am I still missing something?

So far Ohio, Indiana and kentucky  seem like they may worth taking a closer look at ( a purely numeric observation). 

Observe people who are already doing what I want to do; people, podcast, videos, and books.

Thus, take this as mere casual observation.