I'm not quite sure actually. There's quite a bit more prestige in her marrying the Dauphin and future King of France than the King of Scots. It seems like Henry and Catherine wanted a more prestigious match for their daughter. First with the Holy Roman Emperor and then with the Dauphin. If the Dauphin is betrothed to someone else then it's possible that they'll settle for her cousin, the King of Scotland. But that would require finding a suitable bride for the Dauphin.
Yeah, that's definitely true. TTL's Mary won't be the same as OTL's Mary.
Yeah, that's definitely true. TTL's Mary won't be the same as OTL's Mary.