The three parliaments will be one single governing body. Just geographically distant.
And they failed, apparently. You must have the will to do something, and prioritise it. In this case unity. If everyone goes their own way you get OTL, with separatists all around, and outside forces holding...
Instead of dealing with kings in a hierarchy with one another, it might be easier to keep three separate states in the union, with their own kings and parliaments, but have a FIRM commitment that all decisions must be the same. We will have thorough negotiations before every decision so all...
We can assume that the characters would be simplified and easier to write as time goes by. Our letters developed in that way OTL. There could easily be developed ways to write consonants followed by no vowel, and ways to distinguish consonants better, such as d t th and b p ph, so it would not...
I was under the impression that the Saxons dominated North Sea shipping, until Charlemagne conquered them. The resulting power void allowed the Scandinavians to become seafaring Vikings instead.
Is going to Iceland that much different from sailing in the North Sea?
A quick look on the internet gives that the Western plans by Churchill, Roosevelt and Morgenthau all included ethnic cleansing of East Prussia, although Pomerania and Silesia were more German than in our reality.
Churchill's plan even gave Germany Hungary and Transcarpathia, so that might be...
I remember some young Germans back in 1990 saying that Austria was needed to complete unification of Germany. It is not that far fetched to make a new Anschluss, and if there is momentum, we might include Luxemburg and Königsberg and Gumbinnen too, even though no Germans lived there at the time...
Sweden and Denmark had lots of Slavic connections in the nobility during the 1100-1500 period, leaving a number of first names of Slavic origin as typical Danish and Swedish names. Perhaps some permanent settlements could make whole regions or even countries Slavic.