You should get paved roads for aedui and arverni if you have a building_present_min_level market forum in the province, unless 1.5 has messed up that conditional. Let us know if you get them then or not. They do not have the ability to build those nice stone walls. You say "some level of stone walls", but there is either a wooden wall or a fine stone one that you would not have ever seen in a celtic town. We have someone who is trying to work on something else for them, but we don't have it at this point.