Your imagination is the only restriction.

For buy and hold rentals, I like 2-4 unit properties....on the sf versus condos, I have done condos and you just have to look out for more issues related to rent restrictions, dues, assessments, reserves, politics, etc. but people make it work, often buying for less than a single family and letting the association handle exterior maintenance.

Louis has more restrictions when rehabbing buildings than Kansas City does, so this might not be a viable solution for your window issue.  

Odds are that he will work out a deal and it will end on a cordial note.

Some restrictions apply.  

Oddly enough, price doesn't always tell you the quality of the neighborhood, I've seen some Class A prices on some Class D properties.

Its brutally painful when my father has close to 60 units and renters work odd hours So my question is this, what are some good options for landlords who's tenants may not particularly be familiar with the Internet or smartphones?

That seems odd - too good to be true.

The odds of selling to three different smokers is slim to none.

If school district matters, include that restriction.