In my point of view, the problem here isn’t really Lantmäteriet, but the contributor terms of OpenStreeMap that clearly states that you, as a contributor, must ensure you have the right to license your uploaded data as ODbL. Personally, I can not assure that. Lantmäteriet has not given any such permission regarding the recent aerial photos. Historic Orthophotos, on the other hand, are released under CC0 and therefore ODbL compatible.