You want to try and pull theology from these books? Fine, but it's your own mortal soul at stake. Please, I emplore you take time with sufficient prayer and let God show you what He's always been trying to tell the world in the Bible. Use your God-given intellect and search and look for yourself.
Where do you get that from? There is evidence in the Bible itself indicating that the Apostles used the Septuagint (See my previous post to you*). Whose canon of the Old Testament do you trust, the canon of the Apostles or the canon of a Jewish Council that rejected the canonicity of the New Testament?
*In Acts 7:14 St. Stephen says that Jacob came to Joseph with 75 people. The Masoretic Hebrew version of Gen. 46:27 says 70, while the Septuagints says 75, the number Stephen used. Following the Apostles example, Stephen clearly used the Septuagint.