I have since found out that Jared (Jarret) are sometimes dit Vincent.This would explain the Charlotte Vanaut as a missread Vincent in the St J.B. register.I would love to find a copy of the original entry but am not sure where to look.
I have also found a Antoine Loiselle and Charlotte Vincent living together in the 1861 Census of Canada at Chambly, sub-district 7, page 117, line 32&33.
In 1865 on the 24th of July he married a second time Sophie Savage in Chambly and can be found with his 2nd wife and a daughter Marie Louise in the 1871 Census of Canada at Chambly, sub-district 4, page 2, line 7-9.
Sophie and Marie Louise are also found in the 1881 Census of Canada at Chambly, sub-district e-1, page 29
So far I have not been able to find the Census entries for Antoine, Charlotte and any of their children in 1842 or 1851 but they must be there.
I'm confident this is the right track for my Alfred if only for the fact that the name Alfred seems to be quite uncommon amongst the Loiselle's.