In many parts of the country a two unit building containing an upper unit and a lower unit is referred to as a flat.

Save your money and build a  network of realtors , real estate investors and  go to meetups

However, it is hard to gauge the rental potential so many years into the future with new construction SFH and apartments being built in the next few years.I’m worried about the HOA, the rental potential, whether I should keep saving and buy a SFH, or if I should just take the plunge and start building equity.

I'm looking into the Credit Stacking program that Jack McColl runs. Looking for any reviews from previous students. 
It's a program that helps/teaches you how to access business credit to fund your business endeavors...

Do those need to be counted and compared with the hours of work I would perform in preparing the property for readiness?

I have personally been raked over the coals on some south side properties with squatters because I wasn't prepared for the time it would take to stabalize the building.

Likely it's that they legally have to have a physical address and as they meet clients at clients home, have them pick out roofing in a catalog and have it delivered directly to the client, there's no need for a physical building.

I'm considering purchasing a commercial office building that has 4 suites. 

After several years investing as an accredited investor, I’m moving to building my own portfolio of SFH and small multi-family that I control and add tax and passive income benefits for additional investing.

I'm ready to get started, but not I'm sure about next steps.