I personally always mod the Frisians in the same group as the English, and the Dutch in the same group as the Germans. Based on this overview I learned back in high school:
Since I learned this in high school, I'm quite sure this is all pretty basic. It's probably way more complicated than that, but it gives a nice, simple overview. Maybe you can do something with that information?
sure

its close to what I had in mind(the goths is perfectly alive in 1060 though

and they are northgermanic(actually would make more sense just calling the north germanic group for gothic, the whole idea of north "germaninc" is somthing thats alwaysed puzzeld me), my big worry was if the dutch and frisians could be seperated. I will move the dutch in next edition then.
for the cultures there is a couple of splits that im hopeing/planning can be implemented(priority from the top).
the germans to be split in five:
Sachsish, Bayrisch, Schwäbisch, Fränkisch(or maybe Rheinsh?) and Thüringisch
The russians in 5-6:
Slovener( Slavic people from Novgorod, much of the noble class in both Novogrod and Kiev was based on them)
Krivicer(Slavic people from Smolensk area )
Poljaner(Slavic People living around and west of Kiev)
Severer or Vjaticer(east of Kiev) one of them might surfice(but I haven't got a clue to which one)
Væringjar
a third candidate would be to split the Leonese from the Castillian
Wish Italy, even in vanilla, had its own Empire tag for Italy/Sicily/Venice/Latnium Kingdom tags.
Dutch is kind of the midground between German and English, so I'm not sure which it should fall into.
I don't think Dutch is in between English and German. In my opinion, it is much closer to German than it is to English.
yeah, the Angels was much closer to the Norse and the Frisians(all three could even to some degree understand each other)