Does a God exist?

[SteveII]

I have never heard a reasonable  plausible scenario that took into account: 

1) that all 8 authors were mistaken that miracles were happening as they followed Jesus around for 3 years, they were mistaken that he rose from the dead after his crucifixion, and how they worked out the common details in time to start writing to

Not all authors claim a rising from the dead, do they? At least, not in the original versions...
The versions that had stuff added to later on... well... it is known that there has been tampering with at least one ending.... no "mistake" intended, I'm sure!

Which authors don't claim Jesus rose from the dead? Mark? How does the 'original' verses 1-8 not claim Jesus rose from the dead? Did you remember there were 27 different documents? They would have ALL had to been significantly altered to remove the resurrection of Jesus. There is simply no evidence that happened.

2) the pre-existing churches who mistakenly believed the same basic thing (of which were not in close proximity to the authors)

Like I said: Essenes.
The notion of the dying and rising leader/teacher was already present in the region... for some 200 years.
How odd that such a notion would be built upon and embellished!

Belief... that's where the whole building crumbles. Why is belief required at all?
Why would the super-being creator of the Universe and beyond be limited to belief?
Makes no sense.
But it does make sense if said being was absent (at least) and people were perpetuating a notion that seemed to work... once... and still does, in a way... perpetuating the notion of the absent being.
And which better way than to indoctrinate children? https://home.snu.edu/~hculbert/ages.htm

Kirk said it well.... "What does God need with a starship?"
What does God need with you believers trying to convince others to believe in the same thing? Can't he do it himself?
If He doesn't do it himself, why do you impose yourselves over His apparent desire not to impose?

I read the entire Wikipedia article on the Essenes. Did not mention anything about "dying and rising leader/teacher". I think you underestimate the just how radical an idea that a 'messiah dies for our sins therefore allowing a personal relationship with God' is. 

Your definition of belief is off. From Wikipedia: "Belief is the state of mind in which a person thinks something to be the case, with or without there being empirical evidence to prove that something is the case with factual certainty. "