Regarding your inquiry, I have checked several items against my sources and I have not been able to verify them.
(1) You stated that Joseph-Marie-Amable Brisset dit Courchesne and Marie-Louise Thomas dite Tranchemontagne(1756-1799 St-Cuthbert, PQ) were married on August 6, 1781 at St-Cuthbert, PQ but I have not been able to find this information in the marriage registry of St-Cuthbert. You are correct regarding Joseph-Marie-Amable Brisset dit Courchesne's third wife Marie-Therese Corriveaux marriage date.This couple had six children twins Therese (1800-01) and Marie-Petronille (1800-32), Louise (1801-), Julie (1803-),Eustache (1805-), and Therese (1807-). Regarding Marie-Francoise-Genevieve Pelletier (1752-1779 St-Cuthbert, PQ) she was Joseph-Marie-Amable Brisset dit Courchesne's first wife whom he may have married on November 22, 1772 but not at St-Cuthbert, PQ. This couple had at least three children Marie-Joseph (1773-73), Marie-Genevieve (1775- ), and anonymous son (1776-76). When Joseph-Marie-Amable remarried to Marie-Therese Corriveaux it was noted that he was the widower of Marie-Louise Thomas dite Tranchemontgne (1756c-March 25,1799 St-Cuthbert, PQ).
Now regarding the children of Joseph-Marie-Amable Brisset dit Courchesne and Marie-Louise Thomas Tranchemontgne, I have been able to verify the followings;
(1) Joseph Brisset dit Courchesne born July 6, 1782 St-Cuthbert, PQ.
(2) Francois Brisset dit Courchaine born on February 17, 1784 St-Cuthbert, PQ.
(3) Jean-Baptiste Brisset dit Courchesne baptised on January 8, 1786 St-Cuthbert, PQ and married (1)on October 29,1804 St-Cuthbert, PQ to Marie-Francoise Blais (September 14, 1786 St-Cuthbert, PQ-July 26, 1808 St-Cuthbert, PQ) and (2) on August 7, 1809 St-Cuthbert, PQ to Marie-Josephte Jourdain (February 25, 1787 Ste-Genevieve-de-Berthier, PQ-May 3, 1858 St-Cuthbert, PQ).According to the registry Jean-Baptiste Brisset dit Courchesne died on July 30, 1832 St-Cuthbert from cholera as two of his children Angele age 18 and Alexis age 19 at the same time.What a tragedy for this family!
(4) Alexis Brisset dit Courchesne born on October 16, 1787 St-Cuthbert, PQ
(5) Antoine Brisset dit Courchesne born on November 20, 1790 St-Cuthbert, PQ and married on August 10, 1822 St-Pierre, Sorel, PQ to Marguerite Bellegarde.
(6) Louis Brisset dit Courchesne born on November 21, 1792 and died on December 1, 1796 St-Cuthbert, PQ.
(7) Jacques Brisset dit Courchesne born on August 31, 1794 and baptised on September 1, 1794 Ste-Genevieve-de-Berthier, PQ and married on March 30, 1818 St-Cuthbert, PQ to Marie-Esther Brule (Octber 12,1801 St-Cuthbert, PQ-August 6, 1822 St-Cuthbert, PQ).Jacques died on May 19, 1872 St-Cuthbert, PQ.
I hope this helps you.