You had said that your EMG had come back normal.
Did you have one since that time that came back abnormal to indicate that it could be peripheral?

Because things like MS are in the CNS, and peripheral neuropathy points to a problem in the PNS.. and thus the 2 are different systems.

I was lucky in that although the rest of my testing has come back negative, my EMG shows moderate nerve damage of 2 types.

If your EMG is clean and you have things like TN, and nystagmus, and other indicators of MS, then it could be a while for you to get your diagnosis, as its easier to pick up during a flare, and you need to have 2 seperate scans, and another diagnostic test to be diagnosed with MS.

Have you had a spinal tap to check for O bands? (or other things?)

If you haven't had a spinal then thats what I would do.