This seems like a case of lots of small incremental changes being slower, more expensive, and ultimately worse than one big change that addresses the problem.
The office shown is extremely large and already big enough for two people, as was initially tried. The only real problem is the noise.
Instead of having a bunch of work done trying to change the nature of the closet, it seems like the best solution would be to have the contractor construct an entirely new wall dividing the office room in two. Rather than being in a small closet, they now have a large room, with a big window and door, etc. A real wall blocks the noise they're concerned about.
The office shown is extremely large and already big enough for two people, as was initially tried. The only real problem is the noise.
Instead of having a bunch of work done trying to change the nature of the closet, it seems like the best solution would be to have the contractor construct an entirely new wall dividing the office room in two. Rather than being in a small closet, they now have a large room, with a big window and door, etc. A real wall blocks the noise they're concerned about.