See the talk page at https://en.wikipedia.org/wiki/Talk:Alexander_Stewart,_4th_High_Stew...
Given what Sellar says, I wonder why the text (about Jean) remains unchanged - Sellar's reservation is not even acknowledged!!?? As it stands the claim on the page is ridiculous: to suggest that Jean Macrory born before 1210 should not have had a child until 1260. This is the sort of thing which brings Wikipedia into disrepute. First of all surnames had not taken over, so surely her father was Rory (or variant) - so if a stopgap is required (and I think not) surely this should be the assumption. [OK, there is a further problem here as "she" would not have been "mac" - so it is more likely that Rory was her Grandfather and strictly she should probably have been "Vc Rory". However it remains the case that this Rory would not have been old enough to have been killed in battle in 1210.]
Second I estimate James' birth c1251 rather than 1260 (1260 makes matters worse). It is, therefore, likely that she was born c1230x5 - 20 years after the supposed death of her supposed father. Third Given that she was the heiress it is likely that her father was born c1200x10, before the deaths of 1210, but too young to take part in any fighting at that time. Fourth so far as I can see the name James was unknown in Scotland at that time.