2. I find that curious; if it was originally given by Mohammad, the Koran should have been in common everyday 7 Century Arabic?
You need to learn more about the Arabic language. "Modern Arabic" is a spectrum of dialects. The language normally used in broadcasts and other situations where people from different regions need to understand it is a formalized idiom based on a much older form of the language. The written language is not as different from its 7th-century version as the spoken language is. Besides, the so-called scholars quoted in the article (and other scholars with better credentials) maintain the the Koran was finalized in its current form a couple of hundred years after Mohammed.
3. so, it might have had an original Aramaic core, that had been translated into Arabic?
From the standpoint of linguistics and anthropology, that is not an unreasonable hypothesis. Nonetheless, as I stressed above, even as far back as the seventh century, Arabic existed as a written language and could reasonably have been used for this purpose.
I have heard that the Koran is not authoritative when translated into other languages, could this be the reason why?
That's more properly a religious question than a linguistic question. It comes from the orthodox notion that the Koran is the actual word of God, who is alleged to have spoken directly to Mohammed in Arabic. Since translation of anything between any two languages can't help but lose at least a few nuances, translating the Koran into Farsi, Urdu or English would of course lose some of its God-given truth.
4. not sure how you mean this, a break in the tradition, between the originators & the adapters or modifiers into Arabic culture?
When I said that the New Testament is apocryphal, I meant that literally. There is absolutely zero credible evidence that any of the stories in it were first told in the early decades of the first century CE when Jesus is alleged to have lived. The Romans were compulsive, bureaucratic recordkeepers and Jesus would have been the most newsworthy story that occurred in their entire history, yet there's nothing at all about him in their archives. It's quite likely that the "gospels" were woven together out of folktales, bedtime stories and linked to subversive anti-Roman propaganda, along the lines of the heavy political symbology in "Alice in Wonderland" and "The Wonderful Wizard of Oz." Which, fortunately, have not yet evolved into religions.
5. no source documents? could the change from pre-Christian be the missing link? lets say that the early Nestorian priests had died, their early Arabic adherents would want to carry on, but the liturgy was in Aramaic. could this have happened to early Chrisitians who did not know Latin?
I'm losing your train of thought. The New Testament was written in Greek, still the language of scholarship, especially in the eastern lands of the Roman Empire. My remark about "no source documents" is my insulting suggestion that both Christianity and Islam might not be based on actual historical events, but were cobbled together after the time period of which they speak.
6. does anyone here at Sciforums know Aramaic?
That would be remarkable but I'd be happy to see them step forward. I have lots of questions.