Apparently, different branches of the family spell it differently. I've seen it spelled Beneaux and Benneux. The Mulberry bunch spelled it Beneux. The two officers signed their names as such, as did their brother on his pension application. One of my wife's childhood friends back in Mulberry was a Beneux girl whose family spelled it that way.
If that uniform tunic could talk, what an interesting story it could tell.
The next time I talk to my brother-in-law, I'll ask him to tell me the story again. I've forgotten most of the details, but I do recall that a gang of bushwhackers showed up at the Beneux plantation, and that one of the brothers was shot on the porch, and the other was shot while jumping out of a window to escape. The Beneux's were comparatively wealthy and owned several slaves. They say that old man Beneux had a bell-cord hanging near his bed, and he would wake up and ring the bell to wake up his slaves, then turn over and go back to sleep.