This is a great project - to address your last point, I dont think it would just be noise if the user habituated to it. Check out this project [0][1] that maps audible data to vibrations and seems to have successfully re-mapped sense data taking advantage of the elasticity of the human brain.
Another similar project lets people "see" with their tongues [2]
I definitely think using binaural (3d) audio could give users a much more complete and useful idea of what they are seeing so I wish you luck. Great Idea.