The contradiction may be obvious, but I doubt if it is purposeful. I suspect that the 1979 record was made first, then they realixed it would make Buffy too old, so they changed it to 1980, but eddited it badly. Her birthdate is later established by both the air dates and the texual dates of surrounding eppisodes to be in mid or late January. Not sure where the specific date of the 19th comes from. January 19, 1998 was a Monday, which is inconsistent with the events shown in Surprise. I got the 15th by using mentioned days of the week as reference points within the mid January framework, but there is a little wiggle room there because they never exactly say what day of the week it is on her actual birthday, though in surprise it is clearly in the second half of the school week and not Friday. It could have been the 14th, 15th, 21st or 22nd. In Helpless, its not entirely clear if the test actually takes place on her birthday or is triggered a day early, so the days of the week don't help much in pinning down the date, however it is still latish in the week, so those four dates remain eligiable. I haven't seen any texual reason to exclude any of these 4 dates in later seasons.

there are several modern references to moloch in a machinery sense including "howl" and "metropolis". however, i have never seen any reference of him as an elephant lol. why dont u list some references? because you cant.

If you want Moloch to fit literary references then by rights he should resemble an elephant.

I would posit that this episode is not a perversion of religious fact but a unobtrusive literary allusion. Being an English major, I naturally assumed that Whedon was referencing Moloch as Allen Ginsberg imagined him in Part II Of Howl; Moloch "whose mind is machinery," a metaphor for the coldness of industrial capitalization that Whedon may have been extrapolating to include the digital information age. Not only that, but no where in the narrative of the show does it ever directly suggest that Moloch was created in the middle ages; all it suggests is that he is an old form who existed as far BACK as the Middle Ages. He could have been released and rebound countless times before that. And in the mythology of Buffy, could one man's demon not be another man's god?
I'm also a bit confused with your final statement, that everything after the bible is a fabrication. Are you suggesting that everything before and including the bible is firmly set in reality? I would suggest that everything ever written down is a fabrication of some form or another. Fiction and literature didn't just spontaneously come into being after the biblical canon was established; their roots are just as deep as those of religion.
In conclusion, regardless of how intelligent a television show has the potential to be, it's still just a television show and its primary concern should be to tell its own story. The average viewer most likely has no idea who Moloch, the Phonecians, or Allen Ginsberg are, but they will still be able to follow the narrative and perhaps even walk away from it with a different understanding of how the internet affects our ability to communicate with one another. That is the most important aspect of this episode, not where Whedon got his ideas for naming demons.
And I agree, being a technopagan sounds pretty awesome.