You really love that kind of confusion...“With the death of King James, Queen Christina acted quickly. She would see her son, accompanied by those loyal to her, escorted back to court where he would be crowned King Jon II of Scotland with much pomp and circumstance. And then installed in the King’s quarters.
After that all attention turned to choosing a regent.”
James V by Nathan Brederick
“All could see that Queen Christina wish to be regent for her son, unfortunately she was handicapped in two ways. Firstly, the Scottish lords just didn’t like her very much, nothing personnel, just they had been very fond of the previous Queen. Secondly, she was pregnant, and this was taking up a bunch of her time. In fact, many factions were dragging on the regent talks so that the final decision would occur after Queen Christina had to take to her chamber.
Mere days before her lying in Queen Christina would switch from campaigning for herself as regent to backing Cardinal Beaton, the Archbishop of St Andrews and the former ambassador to France. This last part appealed to the continental Queen Christina and her hopes that the French would face off against the English if anything were to happen.
Unfortunately it was too little too late.”
Christina of Denmark by Helen Olsen
“While Queen Christina was attempting to win over various Scottish Lords, the English faction had wooed James Hamilton, Earl of Arran. See, they could get him something he really really wanted: a divorce.
The thing was Arran was married to one Margaret Douglas (not, Margaret Douglas, Niece to Henry VIII and Aunt to little John II, but Margaret Douglas daughter of James Douglas, Earl of Morton) and she was insane. With Henry VIII personally interceding  Arran was granted his divorce. He would then remarry Margaret Douglas (The King’s Niece and King’s Aunt, Margaret Douglas).
With this tie to the English Royal Family, and assurances of at least one royal betrothal, the English through their weight behind James Hamilton, Earl of Arran.
The Tudors: A Real Life Soup Opera
 The pope really didn’t want to risk divorce issues with Henry VIII after how the last one turned out.