Maybe things are different in Boston. The general rule is the older the office the better it will work, and I’m betting that Boston has some pretty old office buildings.
What I can say is that this is a pretty popular political football at the moment. I wouldn’t be surprised if this it was initiated by the mayor and not the planning department.
The shop is making you pay the “janky e bike tax”. No matter. Any 7-9 speed Shimano derailleur will work, and most off brand 7-9 speeds. Acera M-3000 is a good choice, but any will work. Feel free to send any specific models you aren’t sure about.