I typically host single family homes, but have been asked to potentially host an apartment complex of 22 units.

@Khaled El Dorry This strategy is know as a consolidation exchange, and like what @Adam Bartomeo said a single buyer might be difficult to find.

Or as singles and nobody to lean on.

I would highly recommend you work with someone that is either located in the same state as you, or explicitly says they have experience with your state.

I like both of your ideas so I would look for the single where an ADU is permitted or one with a dump ADU to renovate (that's best) and balance that against the purchase of a 2-4 unit.

A lifelong friend and I are motivated to (virtually) meet and connect with those in REI working in the Pittsburgh area.I'm active duty military and living in California with two rental properties (one in Virginia Beach & one in Pittsburgh) and my close friend owns a single family in Baltimore.  

Would it be a bad idea to buy a single family home built in mid 1930's?

The last single point source I have was published in I believe 2014 - so it’s hopelessly outdated.  

Pretty much every small business other than some obscure ones that are excluded (see below) If you have 12 Single Member LLCs that own your rental properties.

I have been investing since 2008 and have purchased everything from single families and duplexes, to 250+ unit multifamily, to assisted living, to shopping centers, to industrial and more.