Hello, I have found marriage and some birth records for your "Arbeau" family. The name is spelled "Arbo". On the marriage record for Nathaniel and Sarah it states he was the son of John and Mary Arbo. Sarah was the daughter of Joseph and Rachel.
I also found the marriage record for John Arbo married to a Beatie Arbo...states John was the son of John Arbo and Mary and Beatie is the daughter of Joseph and Rachel so two brothers married two sisters.
I found a John Arbo with wife Mary and a slew of children in the 1851 census for Balckville, states under "how long in the colony" that it was from birth so he was born in New Brunswick not France. As well they identify themselves on the census records as being Irish not french...but that means nothing as I am french on my dad's side and some of the men married Irish women and so they stated on the census for whatever reason that the family is "irish" when clearly that is not so.
Living in the household next door to John and Mary is another Arbo, hard to make out his name...looks like it could be "Josh" and he is listed with a wife and a son and daughter.
On the marriage records for Nathaniel and his brother John it states both were born in Blackville. I have downloaded all the records I have found thus far and if you would like to write to me at my e-mail address I will be happy to send the records to you...contact email@example.com
Hope you are having a great day!
Sharron Nadeau nee Guimond