Hi Joseph,
First of all, on the matter of proving whether or not there is a special "gospel style" in presenting certain details or not and having to prove that based upon other writings, I don't have to do any such thing. I'm TELLING YOU DIRECTLY this is the gospel style, which could be unique, and since you can't disprove that matter, it's just an issue of my view versus your view. The fact that you're incapable of accepting this view is moot. The only issue of note, therefore, is that you recognize that that view allows me to dismiss hundreds of your so-called "errors". So my word to you is that "it works for me and my acceptance of the gospel" so that's the end of it. You can find as many errors as you want.
But, in fact, I can prove that the Jews in particular did this sort of thing in their writings, one of them being Josephus. But I'm not even going to bother giving you the examples since I'm sure you will then say: "Well show us someone besides Josephus and any others who did this, then I'll believe." In other words, I don't need to meet your CRITERIA to prove what is evident. I only need one example of this parallel detail in Jewish writings which is the gospels, so that's that. You can either accept it or not. It matters not to me. But just because you find in one gospel where Jesus said one thing to a "Mary Magdalene" and you find in another place he said something else, it's your own folly to presume a scribal error without considering these might be two different women and two different incidences. So you can't prove the error.
Now on the point of why God wouldn't want the outsiders to understand the nature of Judas' death or the significance of that point, I don't need to comment on it beyond the fact that tripping up people like you who want to find error with God's works is very much his nature. He likes to trip up the "wise in their own cunning" and to show the foolishness of worldly wisdom.
So he trips you up with these parallel accounts and having the gospels speak of similar accounts but separately so that you think there is an error. A lot of things can be true or false based upon perception.
For instance, if you're walking in a straight line around the earth that intersects with a certain city, say Jerusalem, do you realize that someone might say you're walking AWAY from Jerusalem and someone might say you're walking TOWARD Jerusalem, depending upon their disposition. You can always fly to New York via Hawaii, Hong Kong and Spain, you know. You'll eventually get there, right?
Or if you asked me my age and I told you: "I'm going on 90" that would be true whether I'm 89 or 3. Because everybody under 90 is "going on 90", technically. So while it may be DECEPTIVE and purposely so, it's still not a LIE. Only if I were 90 or over would it be an UN-TRUE statement.
So you have to realize that the Jews, for most of their late history, were under the control of pagan powers and even though they had their own writing and language, they had to find ways to communicate secrets and information without it being privy to their captors. People event these kinds of "tongue-in-cheek" ways of conveying information all the time, like masters of a house talking in a way so that the servants don't understand what is going on, etc.
So a literary style that provides some private information in plain sight of others is not uncommon. Why you have a problem of giving the gospels this benefit of the doubt, therefore, is simply bias on your part. You're trying to apply simplistic concepts to an extremely complex work and so your are finding problems with it. But the problem is you simply don't understand what you're doing.
But please don't STOP! This is amusing and fun to the anointed Biblicalists.
But I tell you one thing; you make me glad I'm an informed "insider". Knowing scripture is truly a wonderful joy.
Have a nice day.
L.G.