I didn't have time to study your word until this morning. I was bringing the boat back to the harbour - going home tomorrow after 6 weeks here
I don't think procity is a legitimate word, Tony. When typing it into dicdotcom, only city comes up. Then procity is not mentioned in any of the related forms, such as intercity, minicity etc. The other forms you mentioned, pro city, and pro-city, also only come up as city. There is no definition of procity, and I have no idea what it means.
As another reference, I checked Oxford Dictionary. When entering procity, it says "No exact match for procity found in British and World English"
So my conclusion is that it is not legitimate.
Got another word?