What about something where you would have to have things usually needed in a city? You would keep the school forever but add a library and academy in EMA. Religious people could have a stone circle or church, non religious would have this as extra space. Having different types of farms from different ages would be needed for a varied diet. The tavern could be replaced by a saloon in IA, houses and military would be improved whenever. Goods buildings could be replaced since trade is a thing. Pick a GB, can be any one, can have it as well as Obs since that is somewhat generic. Event buildings would be allowed but probably only one of each. To make it harder, group similar buildings together and have them in realistic locations, farms on the outskirts, schools near the housing district, factories in the industrial district, etc.