I was told (about 1978) by an Orthodox Jewish Rabbi who converted to Christ, that there are two books that will never be found in an Orthodox Jewish Temple or Synagogue: (1.) Any Greek translation of the Old Testament (EVEN in Greece), especially the alleged BC Septuagint (probably better dated about 200 AD, according to some masters in MSS evidence); (2.) The O.T. Apocryphal books.
This was later told me again by an elderly Jewish man who was converted to Christ in 1986 at 83 years of age. He told me that Orthodox synagugues world wide conduct their worship in Hebrew, even in Greek speaking countries.
I am not Jewish, nor have I ever been inside of any synagogue in my life. I am wondering if there are any Jewish people (or Jewish background people) reading this who know anything about this. Now, the comments that came to me were about ORTHODOX Jewish worship. I've never discussed these things re Condervative or other Jewish worship.
I'm not sure why you mention this, but it seems to me that it is consistent with our hypothesis that a (not 'the') motivating principle behind Jamnia and any possible later Jewish efforts to close the canon was to minimize the amount of stuff that those awful Christians could use.