I wanted to come back and give a more thorough response to this thread.
Well I had been hoping you would respond to my last post, but never mind.
The first accounts of the empty tomb and the eyewitnesses are not found in the gospels, you're right - but they are found in Paul's letters, which every historian agrees were written just 15-20 years after the death of Jesus.
Just 15-20 years? A lot of chinese whispers can happen in 15-20 years, especially in ancient times with no reliable historical record. Oh, and the claims were of a religious nature - we know how much we should not trust religious literature as a source of history (see mormonism and scientology). And those writings of Paul are really sparse when it comes to Jesus. If Jesus really did do all those things we read about in the later gospels, then why did Paul not think to write about that instead of being so vague? Strong evidence that the finer details of the story of Jesus merely assembled themselves throughout years of preaching. Nothing to do with eye witnesses. If however, eye witness statements were used, then claims of flying zombies should be dismissed out of hand.
Paul indicates that Jesus appeared to 500 people at once, most of whom were still alive and could be consulted for corroboration. Paul's letter was to a church, and therefore it was a public document, written to be read aloud. He was inviting anyone who doubted to talk to the eyewitnesses if they wished, which was a bold challenge since during the pax Romana , travel around the Mediterranean was safe and easy. Paul simply would not have made that challenge if those eyewitnesses did not exist.
Or else they were simply people who had known Paul and to some extent were influenced by his message: "Ah yes, the flying zombie went that-a-way".
• Why did Christianity emerge so rapidly, and with such power?
They did a lot of traveling and preaching and came up with a new twist on old ideas as well as borrowing from tried and tested myths of other religions.
• No other band of messianic followers in that era concluded their leader was raised from the dead - why did this group do so?
Because they may have been the first to see a niche in the idea? If not for the zombie aspect to christianity, it would have probably not been successful.
• No group of Jews ever worshipped a human being as God. What led them to do it? Jews did not believe in divine men or individual resurrections. What changed their worldview overnight?
Well who knows if it was overnight or not. And if it's true that no jew believed in the divinity of men, then perhaps the new promise of accepting a zombie as their salvation proved too tempting? The people who converted much later to christianity would not have witnessed any resurrection or even had a clue who the historical Jesus was. All they knew about from Jesus was what they heard from preachers. And we all know that preachers should not be trusted.
• And how do you account for the hundreds of eyewitnesses to the resurrection who lived on for decades and publicly maintained their testimony, eventually giving their lives for their beliefs?
Firstly, you have no proof that people actually saw a flying zombie just as we have no proof that the many residents of Mobile, Alabama saw a leprechaun.