The septuagint was originally only the Torah, just like the typical targums, translations into Aramaic, which was the lingua franca of most Jews. Whoever did the original translation, by the time the Vulgate was written it was corrupt. And we have absolutely no clue who did the translations of Writings and Prophets, or when they did them. This is the order of the Tanach:
Torah: The Books of Genesis (Bereshit), Exodus (Shemot), Leviticus (Vayikrah), Numbers (Bamidbar) and Deuteronomy (Devarim).
Nevi'im (Prophets): The Books of Joshua, Judges, I Samuel, II Samuel, I Kings, II Kings, Isaiah, Jeremiah, Ezekiel, Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum, Habukkuk, Zephaniah, Haggai, Zechariah, and Malachi. (The last twelve are sometimes grouped together as "Trei Asar" ["Twelve"].)
Ketuvim (Writings): The Books of Psalms, Proverbs, Job, Song of Songs, Ruth, Lamentations, Ecclesiastes, Esther, Daniel (although not all that is included in the Christian Canon), Ezra and Nehemiah, I Chronicles, and II Chronicles.
http://www.jewishvirtuallibrary.org/jsource/Judaism/Tanakh.html
Malachi is not the last book, nor does it end with the word curse.
Each of the three sections of the Tanach was canonized at a different time. Writings was the last part to be canonized. I'm not sure what the significance of the order is within each section, but moving Daniel into Prophets does change the meaning of the book. Christians consider it prophetic. Jews do not. Some of the books that were split were treated so because they were too big for printers to print in one volume.
Dauer