Good Afternoon again Shadow Wolf: Speculation as to the literacy of Jesus and the Apostles is generally based on what is known about the times and cultures they lived in, coupled with the writings we have available. for instance, among the Jews of Jesus' time, literacy was mostly the craft of the priest class. A handyman such as Jesus would not have known how to read or write, and probably no one in the small village of a few hundred people that he came from could. As to the issue regarding whether or not these men existed, it is the consensus of most historians that they did in fact exist, and there are non-religious attestations to this, such as the writings of Josephus in the case of Jesus of Nazareth. Now, the question as to whether one of them was God and the other was a Prophet, well, that's where things start to get a little shaky with regard proof. I deal in probabilities. The former is highly probable and the latter is highly improbable. I am familiar with theories that Jesus of Nazareth was a purely fictional character, and one account of how he was a code name among Jewish trippers for psychedelic mushrooms, but this is probably quackery. He probably existed. He probably was not a permutation of the God of Abraham in human form.
As for how it can be approached that the Apostles couldn't read or write, the accounts of their backgrounds would place them (with the exception of Matthew) in the illiterate class. Access to books took money and privilege. Lots of it. None of these men had money. They had a very minimal existence.
You made reference to their respective texts, and I am unaware of any texts ascribed to Jesus of Nazareth. If you are referring to the New Testament, I am unaware that there are any books or collection of letters in it that were written by anyone who ever met Jesus. The Letters of Peter are thought to have been written on his behalf. Most of the New Testament is the work of Paul of Tarsus, who never met Jesus, his follower Luke, who never met Jesus, the authors of Matthew, Mark and John are not thought to have known Jesus. They are works written in the traditions of Matthew, Mark and John, which was a common literary device of the time. What New Testament author knew Jesus, and what part of the New Testament did Jesus write?
All the best,
Gary