For what it's worth, I had anterior C5-6-7 fusion 14 years ago with a plate, and just 2 months ago had an anterior fusion of C4-5 with a plate. To install the new plate, the surgeon removed the old one. Like you describe, the vertebrae fused back then are supposed to be sufficiently grown together that the original plate had long since become unnecessary. He showed me on x ray, and it looks grown together to me (a layman). He reports, with x ray evidence, that removing the old plate and doing everything else turned out just fine.

Since I still have a plate, just a different one, I can't speak to the esophagus issues. I can say that with this newest fusion, the difficulty swallowing, and the breathing and choking issues when trying to sleep, were just awful for the first 2 or 3 weeks. Other than that I have had very little pain and no other complaints.