there are some good common mistake explanations in Absonthered's guide, linked in the first place. it usually has to do with folder names.
you can easily unlock the maps yourself. just change the playableciv tag in WBS. I'm just trying to indicate whats recommended for good AI results.
I just went over all the buildings. balanced the costs. added the tannery and textile factory, both available right away, with production bonuses for animals and plants respectively. didn't remove the regular market but lowered its bonuses (now +20%, 1 merchant), changed the name of the harbor to fishery, the name of the lighthouse to harbor, the name of the drydock to shipyard, effects unchanged, all the corporation buildings require a prereq building in the city + 3 more of another building and have 1 specialist slot and +5% per resource.
gold access at tungul is fixed