Simon Paul Magus
A further possibility: The character Simon Magus, mentioned occasionally in the New Testament, is Paul. This is so because after Paul's conversion it was not really meet to call him that in stories of the antagonism and persecution he organized and led.
Similarly, the character Barabbas, the bandit pardoned instead of Jesus, was actually Jesus himself. There was a slight mix-up in the clerical department, due to the fact of one candidate for release being Jesus bar Abbas, ("son of Abbas", or "Barabbas"), and the other Jesus bar Abba ("son of the father", or "the Rowdy Rabbi") --- and bureaucracy being what it is, Barabbas was crucified, probably with a great amount of cursing and crying, and the real Jesus set free.
This amazed the disciples when a few days later Jesus found them shivering in the locked back room of a mean but hidden sty somewhere in the darker part of Jerusalem; but Jesus was too discreet to tell just how big a blunder the Romans had made; it would be outright wicked to wreck the faith of men who would gain so much comfort from it. (As for how Jesus's mother and others mistook the man on the cross for their son and teacher, well, getting whipped and beaten does not made a gaze linger.)
As for the two men on each side of Barabbas on the cross, recent research has shown one was a healed leper caught stealing as he could legitimately beg no more; and the other was one Lazarus, who had killed a man in a fight that had broken out after his incredible boasts of resurrection had been disbelieved.
This, however, is all according to the Book of Perhaps, which is half lies and half mistakes.