... WILLIAMINA, who married William Moore of "Moore Hall."
Tradition relates that the mother of Williamina, who died in childbirth, had re-
quested that her child if a male should be christened William after her brother,
the Earl of March, and it being a girl was christened Williamina out of respect
for her wish, hence the peculiar spelling of the name. ...
This source is most likely in error regarding Williamina's birth.
According to The Peerage, Lady Anne Douglas, sister of the first Earl of March, died 23 Feb 1699/00 when her clothing caught fire, not in childbirth. Williamina is not listed as a daughter, and Lady Anne had 2 sons between about August 1697 and her death, so could not also have had a daughter.