My Aunt and I have been working on our Blancet family tree for over a decade and we did not get very far, it dead ended with my 3rd great grand father James H. Blancet.
A few weeks ago I decided that my aunt and I both needed to work as a team and started tossing around ideas, sharing facts about what we could prove and what hadn't been proven yet.

I remembered my grand mother telling me she didn't think Blancet was their original surname, that someone had told her their original surname was Agent and changed to Blancet, why no one knows.

As my aunt and I were talking on the phone, she started looking for the Agent surname in the records and she said I got to look at this 1860 census record, so I did go and look at it.
There was a man by the name James H. Agent listed with his mother Sallie and several of his siblings, but that wasn't proof James H. Agent is my 3rd great grand father James H. Blancet, the age was correct, the birth place was correct, but that wasn't proof of anything at that point.

I got the idea that I needed to look forward and went to look for them in the 1870 census and they were not there under the Agent surname, but I did find them now using the Blancet surname!
I kept looking at both census records, the 1860 and 1870 census side by side and sure enough it is one and the same family using both the Agent and Blancet surnames no doubts about it.
But again that wasn't the smoking gun evidence we needed to prove it is a case of NPE, Non Paternal Event, in this situation a surname change from Agent to Blancet.

With this newly found records evidence, I started documenting this Agent / Blancet family of Jackson County Alabama and traced each of the children's trees which lead me to Milam County Texas. It took a ton of genealogical paper trail research, but eventually I found the smoking gun evidence I was seeking, I found the descendants of 3 of the 4 brothers all residing either in the same house hold, or residing right next door to one another in the 1940 census in Milam County Texas.

That is the smoking gun evidence I was seeking, the descendants of the 3 male siblings having interactions with one another by either residing in the same house hold, and or residing next door which was a common thing in those days as family's typically followed one another from county to county, state to state. It gets more in depth then that but for the sake of sparing you all the boring details, I was able to tie in 3 of the 4 brothers, the sons of Sarah "Sallie" Agent nee Blancet, proving they are indeed related to one another.

We had my great uncle Blancet Y DNA tested, he is not a Y DNA match to the other Blancet / Blanscett / Blancett / Blansett family's of Jackson County Alabama, which seemingly tells us that our Blancet tree is a case of NPE.

I say we have only partially solved this family mystery because we need to take it to the next step, we need a male descendant of one of the other 2 brothers, Francis M. Blancet, George H. Blancet to Y DNA test to confirm they share the same Y chromosome as my great uncle whom is a direct descendant of James H. Blancet.

Paper records wise I am 100% convinced this is the right connection, but Y DNA wise we just don't have the final piece of the puzzle and that final piece is proving the male descendants of
Francis M. Blancet and George H. Blancet share the same Y chromosome as my great uncle.

We still have the unanswered question, who is Sarah "Sallie" Agent nee Blancet? Who was she married to, who are her parents? I believe Sarah Agent / Blancet to be a potential sister to Jordan Blancet also of Jackson County Alabama, Jordan is residing next door to Sarah Blancet in the 1870 census, so Sarah and Jordan were certainly neighbors to one another, and potentially are siblings?

We don't have all the answers yet, but at least we have made some serious progress and all it took was finding that one record to point us in the right direction.
I have worked on a lot of family trees over the years, and I got to say the Blancet family tree is one of the most difficult trees I have ever worked on! The paper trials were extremely difficult to prove out for multiple reasons. Some times the death records could not be found, and some death records that could be located, they listed the wrong parents names or gave no parents names at all, making proving things out quite difficult.

I have seen a lot of hearsay evidence be incorrect, but the hearsay evidence with the Blancet family records is almost to the ridicules level because those whom were the informants for those records often gave bad information, or didn't know that information leaving blanks in those records, parents "unknown" type information. The direct descendants of Francis M. Blancet, George H. Blancet, James H. Blancet ( my forefather ) and their sister Margaret Blancet, all migrated to Milam County Texas at about the exact same time period, but the most important record of them all was the 1940 census where 3 of the 4 brothers descendants were either in the same house hold, or were residing right next door to one another.

I have the paper records researched, now I just need another male Blancet / Blancett / Blansett / Blanscett to Y DNA test to give us that final piece of the puzzle.