A three level ACDF will stiffen your neck and increase the load on levels above and below. However, it might be helpful for you to measure the motion from flexion to extension on the lateral motion X-rays. IF you have a highly degenerative neck to begin with and the motion of these three segments is less than ten degrees total, a three level fusion will not cause a significantly notable difference to you.
Surgeons can perform hybrid surgeries. That is a combination of ADR and fusion. You might be a candidate for that procedure but again, this depends upon the quality and degenerative nature of your discs.
I can review your MRI and X-rays if you like. Please call the 888 number and talk to Margaret.