i like the idea but not sure about buildings you mentioned. since most of them giving same benefits already exist. what about jobs like miner, farmer, woodcutter, fisher, barber:)
lets say you can get a mine in iron ports which will increase the products ports get every 3 days. also you will get some tax from controlling that mine.
workshop will effect tool ports.
carpenter will effect wood ports.
farm will effect tobacco and cotton ports,
dock will effect food ports,
pub will effect rum ports,
also you can build them in other ports which will increase the demand of ports as an exchange you will get some tax from each resource sold to that port. lets say you build a pub in food port means that port needs rum. selling rum to that port will give you some profits also buildings amount in each ports will effect the prize of markets.
due to your suggestion the profit could be influence too instead of gold its your call.