The Jewish leadership only rejected them based on the fact that they so strongly facilitated Christian beliefs such as eternal life, the resurrection of the dead, and the cosmopolitan (non-ethnic-Jewish) breadth of the Christian community.
Of course you're going to have to depend on some extra-Biblical authority to determine what the canon of inspired Scripture is, since the Bible itself did not come with a table of contents. The Christians had their councils (Hippo and Carthage) and the anti-Christians, led by Rabbi Johanan ben Zakkai, had theirs (Jamnia). The Christian councils kept the LXX and the deuterocanonicals; the rabbinical council at Jamnia, reacting against the spread of Christianity, threw them out.
Just as they threw the Christians out of their synagogues.
I decidedly agree with Rabbi ben Zakkai that the LXX with its whole 45-book canon strongly confirms the Christian perspective. That's why he was against it, and that's why I am for it.
Reference: http://tinyurl.com/LXX-jamnia>
No, long before the christian era Jews did not count them as inspired . They included them in the Septuagint because the books told of the history of Jews between Artaxerxes and the Roman era. However, Jews even before Christ's birth did not believe them to be inspired.
The Christian councils kept the LXX and the deuterocanonicals
But they are not included in the early lists of inspired books. It was only in the 16th century that they were declared canonical by catholics.