And what you are ignoring is the fact that there is no proof of any BC Septuagint even existing.
When Origen made his copy of the Septuagint he had a copy of the New Testament in front of him and simply made the Old Testament verse match the New Testament one.
Now stop talking as if you have proof of anything-you don't.
So, while I acknowledge your Septuagint denials, I do not take them seriously. If you are going to deny everything, why bother joining the thread? If you are going to use margins among scholars who have an agenda (like Paul Kahle, a Lutheran scholar of the Hebrew bible, for instance), it's better not to even post anything because such views do not lead to any further discussion or learning.
The fact is that the Apostles used something other than the Hebrew bible (if we can speak of individual scrolls as the "Bible" that is). Whatever they used they considered it Scripture. The fact is there are Greek-language fragments of the Old Testament that pre-date Christ. Chances are the Greek-speaking Jews used them, as no known Greeks before Christ showed much interest in Judaism.
Josephus quotes from and mentions the Septuagint in the first century. He claims it consisted only of the Torah, but Josephus was a Pharisee and definitely not a Christian, and therefore is not an unbiased source. Philo mentions it too.
So, there was something as early as 70 AD that was called the "Septuagint." As far as I know, there were no copy-right laws or quality controls. It took the Church 300 years to agree on which scrolls of some 200 in existence at that time comproised the Christian canon, and many churches in the meanintime used noncanonical or even non-Christian sources as inspired texts!
Various copyists and versions of the Greek Old Testament found their way into the Christian world without anyone being able to compare it to some other versions.
Theodotian was a Christian convert who lived in the middle of the Christian Ephesus.When he rendered his 3rd century OT translation of the Hebrew OT in Greek, the Christians and Greek speaking Jews probably said "Great! We now have the Scripture in Greek to read." It's not like someone had all these cross-references to check for factual errors before it was released into the general circulation.
Most of the faithful today would not be able to distinguish a Gnostic text from a genuine gospel. Most people are not that well read and educated in biblical studies, myself included, to be able to say "Aha! this must be one of those versions made by Aquila because of Semiticisms and language style!" Most people would make nothing of a marginal or textual insertion of a Hebrew word here and there, even if they could read Greek and Hebrew.
But, the Church did not develop on what was written in any particular version of the Bible. The Church was teaching the New Testament orally for decades after Christ, and only committed to writing the Gospels from memory towards the latter half of the first century.
St. John Chrysostom in his Homily observes that God's truth was not meant to be written down, but that our corruption made it necessary.
In other words, the Church was aware that not everyone who wrote biblical "stuff" in those days was inspired and filled with Spirit, and therefore what we have, from the copies of the original Gospels is but a human rendition of what used to be inspired and is now made corrupt with various authors and scribes.
So, the written word becomes "second best," for God did not write the books of Moses; Moses did, not for himself, but for the idolatrous Jews. Christ did not write for his disciples but they did for us.
And then we copied them and copied them and are still copying them in endless and imperfect versions. Does that mean we have to reject or deny them? No, because we have textual criticism to arrive at some semblance of the 'true' version, even if such a version does not exist, just like the LXX.