Other mistake: Grand-Santa has made 70 missions, and Santa (Malcolm) has just completed his 70th mission, totaling 140 years. Yet Grand-Santa is only 136 years old.
Suggested correction: Grandsanta's portrait is shown in the halls of the North Pole with the dates 1902-1941 (with Malcom having done 71 missions from 1941). Therefore he did 39 missions. That makes for a total of 109 years, meaning he was 27 when he took over from his own father.