Gerry, your Mark/Remark theory is silly. It's called wishful thinking. I find it as likely as the Chariots of the Gods. I could use your reasoning to justify anything. Well, you see, there might have been another writer who wrote a true, alternative account, but all traces were COMPLETELY destroyed.....

Are there any serious or irreconciable inconsistencies in the Gospels?

Those examples of Pilate's behaviour which you cited were what was being held over his head that day. Also, they threatened to tell Caesar that he had ambitions to the throne. With Pilate's track record, that story would have been swallowed hook, line and sinker.
Pilate's weakness here is of personal integrity. Anyway, here are some points to consider. I'm drawing from the 4th volume (the Roman Byzantine Period) of the History of Eretz Israel. Edited by Menachem Stern and published by the Yad Itzhak Ben-Tzvi centre, one of the most respected academic institutions in Israel. At the start of Pilate's rule, he placed banners in Jerusalem bearing depictions of human and animal figures, a big no-no. A Jewish delegation left for Caesarea, to protest, but Pilate called his army and threatened to massacre the crowd unless they all returned to their homes. Those gathered prostrated themselves saying that it was better to die than to see graven images in Jerusalem. When Pilate saw how serious they were, he gave in to their demands. Seems to me that he realised that it might spark massive unrest.
Another point that encyclopedia makes is that for the early part of his rule, there was nobody in Damascus for the people to complain to. When there was, Pilate was a little more cautious.

As for the 'impossibilities' of the trial, the Gospels make it clear that this was done very improperly.