"But from your (confused) cumulative view, all the lamb details in John would have utmost importance to the other stories. YOU project from your own modern reckoning what is important or unimportant ONTO these stories in your "harmonization" of them."
To recap, You offered what you thought was a contradiction between gospels, I offered a harmonization to show there is no mutual exclusivity. I merely compared the texts as you compared them, only with a different conclusion. This talk of cumulative views and importance of stories is all irrelevant. It doesn't matter who wrote any of the accounts or even if they are false accounts to make my point. In a logic class you deal with arguments, some of them may have obviously untrue premises, but you accept them provisionally to examine the argument form for the purpose of learning the forms and how to recognize things like contradictions and other logical fallacies. You still don't know what a contradiction is. I don't know why your mind shuts off every time I say this: "If any harmonization is possible between truth values, even if the harmonization is not an accurate representation of what happened, and even if the accounts are not true, then there is no contradiction." I haven't really addressed whether or not the Bible is true, just that what you've offered is not a contradiction. it's a very simple point, I don't know why you over complicate it with irrelevant stuff. Perhaps you are a relativist who does not believe in truth or logic?
"Curious definition you have of "isolated". I'd love evidence that the early schools of Christian thought each knew (or even cared) of the other schools' existence. Otherwise they sound pretty isolated to me."
What are you smoking? I specifically mentioned the uthmanian revision, which is where Uthman collected all variants of the koran and burned them so that there was only one version left. Something like that never happened with the Bible. There are thousands of ancient new testament manuscripts which have been recovered from different geographic regions in different languages from different textual families showing that they were not isolated textually. If they were isolated there would not be different textual families.. as for how many scribes knew how to write, that's irrelevant because of the thousands of ancient new testament manuscripts have been found. On top of what was found, consider how many must have been lost to age, decay, and persecution of Christians, and then you might get a better idea of how many people were copying these texts they thought were from God. I've conveyed an argument from textual criticism but you've taken it as something else, bringing all sorts of irrelevant information into it. You don't seem to understand arguments very well, at least that is how you come across. Though it's also irrelevant, try reading the ante-nicean church fathers and read about the disputes Christians had over doctrine to see different schools of thought within Christianity, but I really don't think that that is what you mean by schools of thought, I'm under the impression that you have some strange mythology about church history in your head which has no basis in reality, but rather in a mangled view of anti-christian liberal scholarship.
"why would they have known of one another?"
Irrelevant again. has no bearing on harmonizing a contradiction. Aside from that, are you talking about Matthew Mark Luke,John and their scribes? The apostles ate dinner together with Jesus, they were chosen by Jesus and had fellowship together, they aren't total strangers. The gospel accounts were circulated among churches early on, this is why we have textual families in such widely different geographic regions with different textual variants in different languages. There were many groups of Christians consider those on the Malabar coast of India which were isolated from the western church and had gospels from a Syrian textual family. When they finally came in contact with the western church, they discussed things and united with them for a while until they realized they didn't totally agree on things.
"even today, "secret mark" and the johannine comma are not common in modern bibles. (That wasn't a "loss"?) But wait, there were "multiple lines of transmission"!"
I'm under the impression that you aren't familiar with the things you throw out there.. did you find these on an atheist website and just throw them out there without looking into them? The johannine comma IS in just about every bible, but they include a footnote pointing out that it is not in the oldest most reliable manuscripts. That is thanks to textual criticism and multiple lines of transmission. It is because there were multiple lines of transmission, that we are able to see that the johannine comma was a later interpolation, but again, this is totally irrelevant. Jehovas witnesses and other arians are usually the only people that care about that variant. Everything in the johannine comma is taught elsewhere in scripture. It could have been a footnote some scribe wrote in for their own personal reminder and then another scribe who copied it didn't realize it was just a note and included it in their copy, and then all subsequent copies in that textual family had it. Secret mark is a different story, but there will always be people who try to lend validity to gnostic gospels and other absurdities despite their obvious failings.
"And now we have the gospel of judas. If this account were vetted and found to be from before even 200 AD, would you similarly compile its details into the others? What about the gospel of thomas? Are you simply going to discard any validity of these more recently discovered accounts to avoid cognitive dissonance?"
I've read the gospel of Thomas and found it to contradict the biblical gospels, so in answer to your question, I would at least "compare" it even though some think the liberal scholars are wrong about it's dating, but I would not necessarily believe it is true or accurate. It has no semblance to the Thomas of the Bible or to the tradition of the churches he established in India. I will consider it before I discard it, you are the one saying that comparisons shouldn't even be considered.. but you contradict yourself because you compare gospels to allege a contradiction, but you oppose comparison to provide a harmonization of the alleged contradiction, so you have a double standard.