(1) It is a problem for those who claim Jesus was supernatural.  The Gospels recount Jesus as being followed by hundreds of people, yet none of them took to writing the events down.

(2) What we have came only after the destruction of the temple in the year 70, (conservative dating for the authorship of Mark) and was not a first hand account.  It was also anonymous.  We do not know the author and the dating is tentative.  We just know that it is sometime after 70.  Fundamentalist Christians, or very conservative scholars, will place the dating exactly at the year 70.  Many scholars are comfortable with it being around 73-75.  Some scholars date it much later. 

(3) The other Gospels came much later.  Luke-Acts came during the early-mid second century, almost a hundred years after the events supposedly happened.

(4) The Gospels get more and more fanciful as they go on, which is saying something because Mark is pretty fanciful to begin with, indicative of legend rather than history. 

(5) The other Gospels copied off of Mark, who clearly was writing fiction, using plot creation and narrative to invent scenes in his story. (See my blog articles for more details)

Paul does not believe in a historical Jesus.  See this article for more details.

Yes.  The legend of St. Genvieve.  You may also consider looking into American legends like Washington cutting down the cherry tree, Pecos Bill and Paul Bunyan, etc...  For more in antiquity, Romulus and Remus, etc...

You do realize the average life expectancy was 45-50 years in antiquity?  That does not count the infant mortality rate, which would cut that number in half.

The women are a part of Mark's narrative creation.  Earlier Mark has Jesus say his kingdom will be inherited by the meek.  He (Mark) continuously shows through parable what this means.  Jesus says to be like children, representative of where Mark got this quote from: Paul, who says that we should be like children in sin, but mature in life.  This passage is also representative of where Mark learned Greek - from Homeric epic (a widely ignored fact in scholarship up until a few years ago).  The three women represent in Mark's gospel the three women who also visit the tomb of Hector in Homer's Iliad.  Mark at times makes these startling but obvious references to Homeric epic throughout his narrative.  You can consult Dennis R. MacDonald on this issue, who has published quite a bit on trope usage from Homeric Epic. 

Actually, most scholars today accept this probability. 

Nobody was intending to lie, nor "sell" the lie.  There is no deceit in fiction writing.  Just entertainment, and for Mark, it was also for esoteric reasons.  Mark would have been writing for a community which already accepted this narrative as fiction.  Because later Christians were unaware of this fact, for whatever reason, is not as relevant.  Your conclusions here are not helpful.

First, Celsus was not a critic in the first century.  He wasn't even alive in the first century.  Celsus wrote at the end of the second century, in the late 170's.  By this time, Christianity had an established Orthodoxy, called the universal (or Catholic) church.  Before this period, there was no established Orthodoxy.  Even after this century, all the way up until the beginning of the fourth century, there was no established single Christian church.  It would not be until the later half of the fourth century, by an edict from Athanasius, that there would even exist an "established" canonical New Testament, although the process would continue (canonization) until the Council of Trent, over six hundred years later.  You cannot use Celsus in c. 178, some 130 years after the first Christians composed any letters, to produce socio-cultural information for the first century.

Based on what evidence? 

This is a naive position.  Mark, Matthew, Luke and John did not know each other, and wrote in different parts of the known world, over a period of some 130 years.   They were also not the original names of the authors--which nobody knows--and were only named such by later Christians in the second century. 

Get your facts straight please.