Earlier quoted context omitted.
As I see it, the rotary dial is the main feature, the rest are just nice things to have (that you can get elsewhere from many dumb phones). It's an extremely cool project and I can't wait to get one!
You know you can just get a vintage one for a song, real beauties, heavy enough to clobber a would be assassin. https://www.ebay.com/sch/182098/i.html?_from=R40&_nkw=rotary...
Someday I'd like to try to use them as an intercom/hotline between the house and workshop, but I haven't figured out how to power the circuit and (especially) the ring signal. (Grandpa always did his own phone wiring and told me you really didn't want to be touching the terminal when a call came through, something like 100V AC!)