How sure are you that your sources are not biased? I know Grabbe is super-biased. His view is that fundamentalist Christians cannot be objective scholars because they are proving a given fact, i.e., for example the inerrancy of prophecy. But is that not exactly what you and Grabbe are doing, proving a given fact, i.e., the errancy of prophecy.
Let me make it easy for you. You have to choose one of these. I know which you will choose, but that's your prerogative. I'll go with Mary Joan.
Professor Lester L Grabbe argues that there was no decree but that there was a policy that allowed exiles to return to their homelands and rebuild their temples. He also argues that the archaeology suggests that the return was a "trickle", taking place over perhaps decades, resulting in a maximum population of perhaps 30,000. Philip R. Davies called the authenticity of the decree "dubious", citing Grabbe and adding that arguing against "the authenticity of Ezra 1.1–4 is J. Briend, in a paper given at the Institut Catholique de Paris on 15 December 1993, who denies that it resembles the form of an official document but reflects rather biblical prophetic idiom." Mary Joan Winn Leith believes that the decree in Ezra might be authentic and along with the Cylinder that Cyrus, like earlier rulers, was through these decrees trying to gain support from those who might be strategically important, particularly those close to Egypt which he wished to conquer. He also wrote that "appeals to Marduk in the cylinder and to Yahweh in the biblical decree demonstrate the Persian tendency to co-opt local religious and political traditions in the interest of imperial control." (Wikipedia)