So Navarra in 867 starts with absolute cognatic inheritance law. This makes the throne fall into the hands of a muslim ruler's wife. While I think Navarra did allow women to rule and thus it is historically accurate, the results are not. Just for game balance Navarra should have agnataic-cognatic. If Valencia and Galicia were introduced in the last release just for balance, as quoted from the devs, I think this also requires to forget historical accuarcy for a moment.