Since he is renting a unit, this is a common way for investors to contact homeowners seeing if they are looking to sell a property.

Is that common practice in your experience?

Large common areas would make it a very appealing rental for 4 people, and location 3 blocks to Macalester College and still close enough to two neighboring universities that the demand will always be there for rental.

Or are there other expenses the owner would have to pay (utilities, dumpster, common area maintenance, etc....)

I fix some of their problems and I have been fixing issues in the common areas. 

As @Jonathan Greene mentioned it can be that the relationship is not well enough developed, however I’ve pitched opportunities to some of my closest friends who have given similar objections simply because all they’ve ever Interested in are common stocks, REITs, and mutual funds.

Is this common?

It's impossible that your politicians have less common sense than the ones here in NY do.  

These list agents have often been in the industry much longer than I have been so it must not be as common among strictly retail transaction realtors.

Depending on your area this can be semi-common or totally unknown.I recommend spending some time researching Subject To conditions inside Bigger Pockets (I think there's an entire podcast about it) to better understand how it works in comparison to a land contract.