Following my own advice in post #6, I pulled out my (Protestant) [Charles] Ryrie study Bible which is based on the American Standard Version.
He mentions that some 29 direct quotations from the Old Testament (all the OT quotations in Hebrews) and some 53 indirect quotations are all from the Greek Septuagint.
Are you familiar with the issue there? Catholic Bibles rely on the Septuagint, which contain those 7 books that Protestant Bibles do not have (plus the additions to a couple books that the Protestant Bibles don't have).
So, there could be an issue here of who is using the 'right' Bible, etc. Catholics or Protestants? It would take a deeper study than I am qualified for, to chase these all down, and see if it is only from the BOOKS that are also in the Protestant Bibles, or whether there are quotations from what the Catholics call the Deuterocanonical books, which the Protestants refer to as Apocrypha ("hidden" books -- books which should be hidden from believers).
Ryrie writes in an anti-Catholic point of view, and he doesn't discuss this issue, although he brings the issue up, front and center.
I've been reading Jewish commentaries on the Old Testament ("Hebrew") scriptures. The rabbis and sages over the years have compared the text in their favorite version (the Masoretic text) with the Greek Septuagint (the translation that was made for the Jews who knew only Greek). And, there are the Samaritan text and the Dead Sea scrolls of the Qumran community. And, they make these comparisons for the obvious reason that they are different. There may be other versions out there, like an Aramaic version, as well.
The modern Jews know that the Masoretic text is not an original text of the Bible. It is simply one of the oldest and most complete Hebrew language version.
this is one of the reasons that archeology is so important in Israel, to keep searching for older and older texts, to ensure what the text really says. There are all kinds of text difficulities, to begin with.
If this subject comes up -- about the Septuagint -- you may well just sit there and at the end say "yeah, this is really interesting."
This may be the reason that there are text differences in Protestant Bibles, versus Catholic, to begin with, which may also jump up as an issue in your study group.
God bless your Bible study, and may the Holy Spirit guide you all.