Yes, there are instances of counties contained in provinces and vice-versa, which is why I made the suggestion to flatten the structure. It's not an issue of any concern to me, though, so I leave it to you.
For the parishes, it seems that the categories will be created as needed when filling out profiles. Do you have any objection to subbing them to all 4 categories (county, province, län, landskap) as I did for Västra Ämtervik (S) ?