Divergent accounts are normal with eyewitness. We should be more worried if all the accounts perfectly correlated which would indicate collusion and complete copying. The above proves the accounts (written at a time where information was hard to come by in that era of no paper, no newspapers, and little literacy) were independent.
I've already talked about at least two of the unexplained issues you brought up. As I have said, I have never seen an alleged contradiction in the New Testament that can't be explained.
Some skeptics complain the gospels are too similar, then others complain their too different.
That rationalization is simply pathetic concerning the points I brought up. As to the disagreement of witnesses, that would work if one witness said the man fleeing the scene was wearing a red shirt, while another said his shirt was violet. However, if one witness said it was a red shirt and another said it was green, you really can't rationalize the shirt as being brown. Here, again, are the points I mentioned.
1) Matthew and Luke disagree on almost every particular in the Nativity.
Specifically, Matthew says Joseph and Mary were already living in Bethlehem. Luke says they were living in Nazareth and only went to Bethlehem for the census. Matthew says they fled, eventually, to Nazareth, in Galilee, to avoid persecution. Luke says the returned home to Nazareth. These are direct contradictions, not variants of the same story.
2) John disagrees with the Synoptic gospels as to when Jesus drove the money changers out of the temple.
Since Jesus' disruption of the temple business would seem to be the proximate cause of his arrest by the temple authorities, John's placing the incident early in the ministry of Jesus makes no sense and also is a direct contradictions, again, nothing you can really rationalize.
3) Mark and Luke disagree as to whether both thieves on the cross reviled Jesus, or whether one reviled him while the other adored him.
Again, Luke's good thief is a direct contradiction to both thieves reviling Jesus.
4) There is complete disagreement between all four gospels and 1 Corinthians as to whom Jesus appeared after his resurrection.
Let me just point out one specific of direct contradiction here. In Matthew the disciples are directed to return to Galilee to meet Jesus, which they do. In Luke they are specifically directed NOT to leave Jerusalem. Again, this is a direct contradiction.
Your argument for different witnesses giving different versions of the same general account doesn't hold up in the face of the many direct contradictions. The reason for such great diversity isn't different witnesses giving different versions of the same story. Rather, the reason is that
none of these gospel writers were witnesses. Their writings are hear-say.