Placide Gaudet identified the Joseph Breau who married Marie-Blanche Boudrot about 1760 as the son of Ambroise Breau and Marie-Anne Michel. I can see no reason to doubt Gaudet's conclusion. Indeed, Gaudet might well have had access to any number of Joseph Breau's grandchildren, some of whom would only have been twenty or thirty years his senior, and they could have provided data which might have made it quite clear that Joseph was Ambroise's son. For example, Gaudet indicates that Joseph Breau had a brother Paul who also lived at Memramcook, but who never married. This is apparently the Paul who was the godfather of Joseph's daughter Hélène in 1770. The register of Beaubassin shows that Ambroise Breau did indeed have a son named Paul who was born in 1741. So Gaudet's statements seem to be borne out.
Marie-Blanche Boudrot meanwhile was a daughter of Pierre Boudrot and Cécile Robichaud. This identification comes from me. It is based on the dispensation granted upon the marriage of Joseph and Marie-Blanche's son Joachim to Victoire Blanchard, at Richibouctou Village, Apr. 10, 1809. This record shows that Joachim and Victoire were second cousins once removed. Victoire Blanchard was a daughter of Joseph Blanchard and Marie Henry, a granddaughter of Anselme Blanchard and Marie Robichaud, and a great-granddaughter of Jean Robichaud dit Cadet and Marie Léger. By placing Marie-Blanche in the family of Pierre and Cécile we can explain the relationship, because Cécile was a half-sister of Jean Robichaud dit Cadet (see DGFA, pp. 1404-1405).
Now, I am sure that you are going to come right back at me to ask who the parents of Pierre Boudrot were, but I have to tell you that I cannot say. I have been unable to pin him down.