Billy has as a dit name Courville. Geneviève only used Courville on any record found.
Now for the father's 2 marriages, sorry for Mr Beauregard, but the evidence found on going through the Drouin records is that from the first marriage of Pierre Deshaies dit St-Cyr with Marie josephe Moreau, the only son with the name Pierre found is named Joseph Pierre, born in 1728, and marries under the name Joseph Deshaies with Marie Josephe Généreux in Berthierville in 1759. The second marriage of Pierre the father to Marguerite Agathe Lefebvre dite Bélisle only has one child, Pierre, born in 1745.
Pierre married to Geneviève Courville: Pierre Deshaies dit Sirène - Cyrène or dit St-Cyr - died in 1812 and is given an approximate age of 70 on the record. So 1745 is much more likely for his birth.
Joseph Pierre married to Marie Josephe Généreux could not have remarried, they both lived to a ripe old age, he died in 1810 and his wife in 1808.
So merges are in order.