Interesting. Thanks for the links.
"Part of Islam was derived from Gnosticism, but much of it is derived from ancient Arab religious beliefs."
And from the influence of Nestorian monks on Mohammed. There were also various strains of Marian heresies, including on in which she was worshipped as a goddess which worked their way into Mahammedanism. Nestorianism still exists in pockets here and there from Syria to China. Most of its influence elsewhere is seen in certain Protestant views of the nature of Christ. Of course Judaism had a major influence, especially on the nature of the mohammedan god allah.
specifically, the Christology of Islam comes from the Gnostics. I can't wait to see how the Gnostic gospels are really the foundation of (Sola Scriptura) Protestantism, but I am sure I will see it on this board.
An interesting study might concern the recent embracing of the Gnostic gospels by parts of our culture, and the inability of certain quarters (is there overlap?) to criticize Islam.