All these questions could be answered with a phase 3 open trial, where they start offering it to the public and that's what I think will happen.
Also, let's not get too hyped about this. Will McLean seems to have indicated his belief that restoring hearing will treat tinnitus, and I think that is true as well, but for some or many of us, this is not simply the case. If we have disregulated nerve synapses then this might not do anything for us, unless the disregulated synapses are staying disregulated because of the loss of input from lost hair cells, which might be the case. One thing I don't believe is that tinnitus starts in the brain unless you have a brain injury.