I'm a full-time employee with no recent self-employment income. 

You might get hospital employees, traveling nurses, or some lower income families depending on the neighbors.

I am owner and single employee of an S Corp. 

I've seen or built dozens of systems using Podio ($24/month per employee user), Twilio ($1/month per number and $0.01-$0.03 per text depending on # characters), and Slybroadcast ($0.05/voicemail).Follow up Boss might be interesting product for you to look at as well.If you want something free, take a look at Google Voice.

Management afterwords is just the necessary requirement to usually run that type of model.I have heard others on the residential side managing hundreds of units to make after their employees maybe 60k a year. 100k if they are crushing it.

Find out how many employees they have.

In fact it would be nice if local gov employees were more engaged, as they would understand the problems we as professionals face and help improve the marketplace, either through policy or procedures; making the community more successful in general.

Which employees are vital to go from a few flips to 20+, such as personal assistants, marketing/sales associates, project manager ect?

I was actually doing some research on maybe hiring a part-time intern or employee to help out and came across that job listing.

The big upside to this property, and a major part of our reason for investing in it is that it is within 3 miles of major medical complexes that employee over 10,000 people, and are continuing to expand their reach in the area.