I don't think that the elective law should be present in Sweden in the 1337 scenario, by that time the election was more of a ceremony. The kings more than often decided their heirs. I think that salic or semisalic gavelkind should be the law. Magnus Ladulås gave his sons a big part each tp prevent civil war, and Magnus Eriksson gave one of his sons the title King of Norway and another the title King of Sweden.