Wow... okay... hm. I'll respond mostly to the OP, if only because that's what caught my attention and prompted my response.
I'm a scholar of Religious Studies, and my particular area of study is Christianity (especially between 200-300 CE), so I thought this would be an interesting thread to pop in on, and see what was being discussed. I must say that I found the OP's description of Christianity very... um... curious? Suffice it to say, I've never heard any scholar describe Christianity's origins in those terms. Nor have I heard any scholar of the Hebrew Bible outline the Jewish people's history quite in those terms. Yes, polytheism likely influenced Judaism to a great degree -- scholars argue that this is why Judaism developed such strong monotheism, to contrast themselves from their neighbors -- but to speak with such confidence about that which occurred in 3000 BCE is astonishing to me. The records we have of the Jewish people -- including of Abraham -- date from much later than that. We can't say much of *anything* confidently about Judaism before the exilic period (that would be the Persian exile, for those keeping track) because the Hebrew Bible wasn't edited, compiled, or in many cases even written until that time. Even things like dualism (the OP's reference was to Satan, I believe) are acknowledged as having come into Judaism, but not from the 3000's... but from the Zoroastrian influence. I'm not saying it wasn't there earlier, but I'm saying that the early history of the Hebrew people is not nearly so clear.
I am understating my astonishment at what was written as "fact" a bit, if only because a good scholar of religion will tell you that nothing from that era can be fact (disclaimer: that includes everything I write in this post... although I will say that most of what I have learned is in accordance with the positions held by the majority of the academy). But... wow. I'm quite honestly at a loss for what to say, but I will try to add something constructive to the discussion.
As for Christiantiy, since that's what this thread is supposed to be about, I'll try add what I can in the few moments I have. Michael Chui's post was quite good on bringing up a lot of things about the councils, etc. that were left out of the OP. The OP's modern account of the history from Luther on isn't bad, if not a bit selective, but I really question the history of the tradition as described (for similar reasons to Michael Chui). For example... the first interpretations of the Jesus-movement were written by Paul, not by Matthew, Mark, Luke or John. The Gospels came about 30 years after Paul, 60 years after Jesus (approximation going on here).
The statement about the "Historical Jesus" in the OP was pretty much bang on, but I'd recommend that posters do some additional reading on the rest of what was said. If only to recognize that things weren't nearly so cut-and-dry as the history presented here might suggest. I can recommend some books for those who are interested. Then again, even to speak of "Christianity" before the mid-400s (CE) is pretty much a misnomer. There were Christianities (plural), but not one authoritative set of doctrines. For example, in the early times, many Christ-followers did not believe that he was divine, some thought that he was, and some thought that he was some sort of hybrid. And that's just one issue. But it was a divisive enough issue that it eventually led (in part) to the split between the Eastern and Western church (what later would develop into Roman Catholicism and Eastern Orthodoxy).
As for saints, martyrs and Mary, in Religious Studies, we refer to this as a difference between the popular religion (what the people actually do) and what the official religion is (what the official doctrine is that people ought to do). There was a whole debate in the early Christianities about the nature of Mary and whether or not she was to be venerated (look up Theotokos on Wikipedia for a brief intro). I might also suggest the wonderful work of fiction "Our Lady of the Lost and Found" by Schoemperlen. While "only" a work of fiction, it is wonderfully researched, and is a great introduction to the so-called "cult of Mary" (disclaimer here again: I'm using "cult" here in a strictly technical sense, in which it does not have a sense of degradation like it does in common usage)
I don't have time to go into all the other wonderful discussion going on in this thread -- alas, time is fleeting -- but I will try to pop in now and again. It's already a long post anyway, and I don't want y'all to have your eyes permanently glazing over.
Also, I apologize in advance if anything I've said comes across as short or accusatory... that's not the spirit it's meant in... more than likely, it's just the stress of end-of-term.