Recovery following a peripheral nerve injury is highly variable and depends on the initial severity of the injury, type of injury (demyelinating or axonal), and distance from the healthy part of the nerve.
therefore I cannot really tell how much more recovery you will obtain. My comments are tempered by not having examined you or seen your tests results, so they are limited in scope
Usually by one year the maximum recovery is obtained. The fact that the nerves are shorter and more proximal is a good thing and I see that yo uhave already made some recovery.
The EMG is consistent with an old nerve injury, and probably quantified the amount of active muscle units left - you do not provide this information though
At this time there is nothing apart from physical therapy and time for the bodies healing processes to work for this type of injury. Surgery to try to reconnect nerves is unlikely to benefit you but if you want to pursue this you would need an expert opinion. With your relatively good recovery you would probably not need nerve tranposition surgery (attaching another nerve to the damaged nerve)
The symptoms in the 4th and 5th digits are likely not connected to the original injury and may indicate an ulnar nerve compression which can by evalauted by EMG