The LeMoine de Longueil (Longueil is on the south shore of the St Lawerece River, across from Montreal) family was headed by Charles, who came from Dieppe, (Normandy) France. The most famous was his son Pierre Le Moyne d'Iberville. Amongst the Longueil papers is a document establishing the affiliation of Charles LeMoyne to the counts of Normandy (although the coat of arms is different), Louis XIV accepted it as sufficient proof of identity. But his father was supposedly an inn keeper, not a career befitting a noble family. Roger LeMoine's text also notes that Jean married the daughter of a notable family, and Charles married Catherine Primot. Also the Chevalier Dominique-Emmanuel Le Moyne de Longueil acknowledged the relationship between Jean LeMoyne des Pins and Charles LeMoyne de Longueil, citing the existence of ancient documents. Monsieur l'abbe Ferland stated in his Notes sur les Registres de Notre Dame de Quebec : "Jean LeMoyne parait avoir ete proche parent de Charles LeMoyne de Longueil". Charles LeMoyne de Longueil referred to Jean LeMoyne des Pins as "mon cousin". The only ancient French Canadian land tenure still recognized by the British noblesse, is the Barony of Longueil, that was formally recognized in 1880 by Queen Victoria. The barony is open to female succussion. Edith White's book listed Reginald d'Iberville Charles Grant as the 8th Baron of Longueil in 1930 with two heir presumptive: 1)John Moore Charles Bienville Grant (b. 1861) and 2)Ronald Charles Grand (b. 1887)).
I have looked at a number of web sites about this title and could find no reference to it.
Charles LeMoyne was considered to be a close relative of Jean LeMoyne, as is cited by Mother Marguerite Marie. And is also described as a close relative by Mother St Thomas.
GM Rose also discussed this relation of Jean to Charles in A Cyclopæedia of Canadian biography.