I assume that the shoulder pain is in your left shoulder more than the right side. The symptoms in your pinky and ring finger sound to me like they are only minimally annoying. The surgeon knows that this area is the region of the C8 nerve or the ulnar nerve and does not fit with your MRI findings of C6 nerve compression (C5-6 severe foraminal stenosis).
The shoulder pain is most likely from the C6 nerve compression. An easy way to diagnose this is to obtain a selective nerve root block (SNRB- see website) of the C6 nerve. Good temporary relief of the shoulder pain (see pain diary) would implicate the C6 nerve and an ACDF or an artificial disc (depends upon X-ray findings) would most likely relieve your symptoms.
ACDF surgery is generally a simple surgery with great outcomes. In the hands of a skilled surgeon, you should have a great result.