Viv, let's do some revision. Do you accept or reject Josephus' testimony? Do you not think he would have been attacked by his peers for lying? What about the report by the liberal scholar John J. Collins? As to the status of the book of Daniel and the date of the documents and their compilation, you have been presented with the evidence. Now you have to accept or reject it. If you believe it to be false, you have to present evidence to the contrary.
Josephus viewed Daniel as “one of the greatest prophets,” because not only did he prophesy future things, but he also fixed the time during which these would come to pass. He was also of the opinion that the book of Daniel was in existence prior to the arrival of Alexander the Great in the fourth century BCE. He viewed the third kingdom of Dan. 2 as Greece , “from the west,” intimating that the fourth would be Rome . Elsewhere Josephus interprets the actions of Antiochus IV Epiphanes as being the fulfillment of prophecies made by Daniel in the 6th century BCE. He also tells of a tower that Daniel had built at the height of his fame, at Ecbatana or Susa (according to Jerome’s copy) that became the burial place of kings. This structure was still in existence in his day, so his detractors could go and see it. 
According to J. J. Collins, Jewish tradition related the end of the Prophecy of the Seventy Weeks to the destruction of the temple, an interpretation that may already be implied in Josephus: “Daniel also wrote about the empire of the Romans and that Jerusalem would be taken by them and the temple laid waste.” 
Daniel as Scripture: At the Council of Jamnia, held after the A.D. 70 fall of Jerusalem to discuss whether certain books should be maintained as Scripture, the place of Daniel was clearly secure. From what we know of the deliberations of the Jewish religious leadership, Daniel’s place in the canon was never even a matter of discussion. It had already been fully accepted. This is established even more firmly by the Dead Sea Scrolls, discovered at Qumran in 1947. Not only were several copies of the book of Daniel discovered, but other scrolls were found which were based upon Daniel-related material. These include the Prayer of Nabonidus, Pseudo-Daniel and the Book of Giants. Roger T. Beckwith discusses different computations of the Seventy Weeks prophecy. In his book he states that the Essenes’ “interpretation of the 70 Weeks is first found in the Testament of Levi and the Pseudo-Moses Documents . . . , which probably means that it was worked out before 146 B.C.” Having also examined dates based on Daniel 9 as calculated by Jewish sects other than the Essenes, Beckwith concludes: “These considerations do not make easier but more difficult the problem of the origin of the Book of Daniel. Nevertheless, they are among the data which, especially since the Qumran discoveries, have been accumulating to necessitate a reconsideration of the common Maccabean dating of that book.”  The latest studies indicate that much of the messianic Qumran literature that depends on Daniel can be dated to before 150 B.C. In other words, by the time of the Maccabees, Daniel had clearly already been accepted as Scripture. On that basis the writer of Daniel could not have been contemporaneous with the Maccabees and the writers of the Qumran material. This adds credence to the Jewish Talmudic teaching that the book was written (or edited) and included in the canon of Scripture by the Great Synagogue before it ceased to operate during the time of Simon the Just (circa 300 B.C.). Jews believed that the canon of Scripture was closed at that point—nothing more could be added. This would also suggest that, contrary to critics, Josephus’s claim about Alexander the Great and the high priest cannot simply be dismissed as patriotic propaganda (see also Ivor C. Fletcher’s Internet article, “Daniel in the Critics’ Den,” Vision-Insights and New Horizons).
 Josephus, Antiquities, Book X, Chapter XI, § 7; Book X, Chapter X, § 4; Book XI, Chapter VIII, § 5; Book XII, Chapter VII § 6 (W. Whiston translation).
 John J. Collins, A Commentary on the Book of Daniel , Hermeneia-series, p. 356, footnote 82.
 Roger T. Beckwith, Calendar and Chronology, Jewish and Christian: biblical, intertestamental and patristic studies (1996), E. J. Brill, Leiden, The Netherlands, pp. 260-262, 275.