I have been reading your excerpt about the Quesnel lineage.
While doing some research, I have found out that Georges de Quesnel and Charlotte Malvoue did not have any descendants.
I found the information in a book dated 1879.
This is the link.http://books.google.ca/books?id=D_wsAAAAYAAJ&dq=%22bre%2...
So Pierre Quesnel, who married Barbe Leblanc?, can't be his son as seen in many family trees who copied that info from Mr. Quesnel's book.
I don't know where Mr. Albert Quesnel took this information about Georges de Quesnel descendants. Since I don't have his book I can't see his source.
Also Hélène Beaumaistre was Catherine de Médécis' lady in waiting as found in the excerpt. I don't know where the name Barbe Leblanc comes from.