My Great Aunt's name was Sarah Inez Rapp Dixon. My grandfather, her brother, was named Kermit Wells Rapp and Henry Isidore Rapp, was another brother. They lived in Nestor, LA. I'm not exactly sure if they were born there. I thought I had heard that they moved to Nestor after the storm washed away the area where they were born. Their parents were Henry and Myrza (nee' Wells) Rapp. My grandfather's grandfather was also named Henry Rapp. They did have a cousin named Royal Rapp that lived on the west bank in Empire or Venice (not sure which one exactly). My great grandmother, Myrza died in 1922 and My great grandfather remarried a lady named Clara. I think there were two other children born after that. I think one was named Aaron. My grandfather also had an aunt named Sarah Rapp Johnson. She was referred to as "Big Aunt Sarah" by my dad, his siblings and cousins. She lived in or around the Carrollton area, New Orleans. I'm sure she probably came from Plaquemines Parish also. From the looks of it, Big Aunt Sarah and Mary Rapp must be sisters. If that's the case, then there was another sister they called Aunt Luthie (I'm spelling it like I heard it). I'm not sure if that's her real name and no one else seems to know either.
I hope this helps some. I'm trying to gather as much information as I can but it's difficult because all the older people have passed away in the family.