So we want to put a soundproof/ sound dampening door at the bottom of this staircase. I'm not sure if that possibly violates some landing codes or anything like that, but this staircase has our dining room on one side and living room on the other, with a hallway directly in front of it. So, awkward placement and it doesn't have a flat wall that a door could just open to and rest against and a sliding/barn door would be very awkwardly sticking out in our living room. I would like to just put a door into the current opening if possible. And before you suggest it, putting a door at the top of the stairs isn't a good option because if you can see in the pictures, the room above has an open bannister from the stairs (looks nice, but probably why noise travels so much). I don't think a typical accordion door would look nice or provide much noise cancellation. I also would like to be able to install a cat door into whatever solution we chose.