Very interesting, thank you. This account has Abraham, Antoine, Galleran, and Anne as siblings, with Anne possibly a "baby sister." Can you tell us what parts of this account resulted from your cousin's research at Montagne-en-Perche?
As for the idea that Anne was Abraham's sister. This was advanced in 1962 by Roland Auger, former director of the Service de généalogie des Archives nationales du Québec. This is related with no details at page 76, Chapter 6, "Jean Côté," of Volume VI, "Our French-Canadian Ancestors" (1988) by Thomas J. Laforest, a translation from the original French "Nos Ancêtres" (1983) by Jacques Saintonge.
You question Anne being in this list as related to her birth year. Some writers say she was born in 1603. Other writers say she was about age 70 upon death on 4 December 1684, making the birth year about 1614.