Sounds to me like you misread my post. I discredited the council of Jamnia as pertinent.
Here's my comment which you can't dispute.
"but the books of the Jewish Old Testament had been set at least 200 years prior to Christ."
I disagree - the Septuagint was worked on by dozens of Rabbis and was the greatest translation effort ever at that time. So, it was not set, that was supposed to be the canon as it existed. Also, the Sadducees, as discussed, would not agree that was the “old Testament” at that time. They were ore strict on the books.