Who says that? That assumption is absolutely incorrect. The Islamic scholastic tradition has painstakingly worked across centuries to preserve every Islamic teaching in its original form. Then add to that the fact that under the said Islamic scholastic traditions anything inferred from or extrapolated upon the Quran and/or Islamic teachings would have proper citation with it, i.e. an academic documentation of how and if the statement or argument is related in what way, shape and form with Islamic teachings. Add yet another fact to these that before Qazvini there is no mention of any such cosmological understanding, not during the time of the Prophet (S.A.W) nor the 600 years after. Lastly the fact that it explicitly states that this was Qazvini's idea.
Under the same Islamic Scholastic traditions your reasoning above would be thrown out the window before even half a glance.
No you cannot. Islamic academic tradition does not work the same way as, say, Christianity. Please read through how Islamic knowledge has been passed down over the centuries.
Again, no, it is not at all. The man was a physician, astronomer, geographer and proto-science fiction writer. None of which grant him any scholarly authority over Islamic thought, nor did he ever claim to have any. Pretty sure there were prominent Muslim masons in Baghdad too. Should their techniques of stone laying be considered the Koranic way of laying stone?
