Even any official kind of reaffirmation is disputed. WP documents, The theory that Jamnia finalised the canon, first proposed by Heinrich Graetz in 1871,[2] was popular for much of the 20th century. However, it was increasingly questioned from the 1960s onward, and the theory has been largely discredited.[3] (Council of Jamnia - Wikipedia )
Sid Z. Leiman made an independent challenge for his University of Pennsylvania thesis published later as a book in 1976, in which he wrote that none of the sources used to support the theory actually mentioned books that had been withdrawn from a canon, and questioned the whole premise that the discussions were about canonicity at all, stating that they were actually dealing with other concerns entirely. Other scholars have since joined in and today the theory is largely discredited.[28] Some scholars argue that the Jewish canon was fixed earlier by the Hasmonean dynasty.[5] (Development of the Hebrew Bible canon - Wikipedia )
As pointed out in your reference, other sources, such as Josephus, affirm what existed in those OT scriptures. So, if the Council of Jamnia did or did not exist it doesn't matter. Their suppose conclusion only verifies what Josephus and other supporting text tells us was the early writings of the church. Thus using the Council of Jamnia as reference (right or wrong) only confirms what exists in other sources.
But hey, if a person can whittle at the credibility of this source and then attack another source, eventually they can destroy the entire credibility structure. Even if it means challenging something 1,800 years later. Hey, why not. Everyone is dead. It also wouldn't be the first time history is rewritten.
As you are very much aware, the apocrypha was never quoted in the standard text nor were there any Jewish sources that confirmed it to be part of the text. It was added 400 years later which is suspect.
But Calvin makes a very simple yet sound argument about the authenticity of scripture:
- John Calvin, Institutes of the Christian Religion, Chapter VII Scripture Must Be Confirmed by the Withess of the Spirit Thus May Its Authority Be Established as Certain; and It Is a Wicked Falsehood that Its Credibility Depends on the Judgment of the Church.
(John never lacked for small titles.)