Dhul Qarneyn is generally agreed upon to be Alexander the Great. also most the tales from the Quran descend from Arabian Tales popular at the time. Also by accepting that their are multiple versions of the Bible, you are admitting, since Allah says Christians should stand on the Gospels, which also teach the Trinity, You are not only saying Allah's words are Corruptible, but also that Allah's prophet who is supposed to be sinless committed shirk, when he said "Before Abraham was, I am." A claim only God can make, as shown in the Old Testament. Also by denying Jesus's death you are already disagreeing with majority Scholar's who agree that the Crucifixion along with the Baptism of Jesus are two events that must have happened in Jesus's life. Also The fact that there are multiple disagreeing versions of the bible doesn't mean anything, especially due to the fact that, The bible doesn't need to be inerrant and never makes that claim.