On the topic of parts, in some ways Motobecane had some of the most unusual stuff. First at least half the Motobecanes I have owned has Swiss bottom brackets which are basically unobtainium. I get replacement Swiss BB from Motobecane donor bikes. On the other hand, Motobecane embraced Japanese derailleurs and brakes much earlier than the other french brands. So those parts should be compatible with other bikes.

On co-ops many are staffed by volunteers, I volunteer at one myself. So sometimes the hours can be erratic. Realize most operate on a shoestring and rely on volunteers and donations.

For a grocery getter/commuter bike, it's hard to beat a rigid frame MTB. They are designed for racks and fenders, can handle almost any width tire, and are plentiful and cheap.