Good point about foreshadowing the Transfiguration scene.
My understanding for the books not written by Paul, Peter or James is not that these books were a hoax. Literary conventions were very different. It was common for all writers of any book to appropriate a famous name to show your allegiance or your education. It wasn't a scam. The scholarship on these books not written by the named apostle is solid. I wonder if the Witnesses have ever alluded to it.
The Bible was not the Bible we know. Many Christians recognizing the differences among the various gospels wanted one gospel combining all elements. I assume w/o the differences highlighted. Others insisted the truth required all four versions. I've never read the actual writings from the canonizing process. Many, many gospels existed. I have no idea why these particular four gospels were chosen.