Take a look at google maps and you’ll see that end of Main St. has mostly fast food, dollar stores/goodwill stores, liquor stores and check cashing stores, not trendy coffee shops, breweries or restaurants (yet).

.- Block and neighborhood safety and amenities (can they walk to a grocery store, for example).I don't think you have to limit yourself to "white collar". 

P.S. you can also look at converting existing buildings (think of closed shopping centers, grocery stores, etc.) as that will save both time and money (if zoning will allow it).

Both in established areas with many desirable amenities (public transport, good schools, grocery stores, jobs etc).

Drug stores and Walgreens in particular seemed very promising until I quickly realized that rent increases were often flat for decades. 

I’m considering purchasing a convenience store/gas station that doesn’t have any land/structures included (just the inventory and leases).

It isn't really a google search item.  

A great place to start is https://www.biggerpockets.com/forums/521-events-and-happenings which you can use to find like-minded people in your area.Besides figuring out what your goals are, how you want to get started, and meeting like-minded people, the first action item would be to talk to a lender.

These are a few items to pin down.

(If possible, please itemize this answer)For items such as vacancy, management fees, repairs, and maintenance, what percentages would I calculate?