Could this have happened? I know Scotland was a center of early Protestantism itself. How would it have affected Anglo-Scottish/ Anglo-Irish relations?
We would likely see Scotland be closer connected with Scandinavia and to lesser extent north Germany with Danish, Swedish and Dutch totality being the main marriage partner of the Scots royal family. We would likely see the large Scottish diaspora to Denmark continue, Scottish mercenaries will be continued to be favoured by the Danes. As such Scotland may take more active part in 30 Years War, which could have a lot of results. It could lead to a more successful Danish Intervention, if the Scottish King decided to support the Danish king intervention.
Scotland would likely also see a influx of French and English Protestant refugees. Which would lead to Scotland likely push a policy of increasing its agricultural expansion in the highland. Scottish surplus population would also have to go elsewhere than America and Ireland.