Yes everything you've said sounds reasonable and possible. But what are you thoughts on more recent events? Please allow me to use the Bible and the time of Jesus as an example. There are some pretty fantastic things recorded about his life a ministry.
Yes, and if we were to use the normal way we judge fact from fiction in books, we would very quickly toss out any notion that the book is factual with regard to his life and ministry. Just like we routinely toss out any notions of truth behind stories like Jack and the Beanstalk, Gulliver's Travels, and Charlotte's Web. It should not receive a special pass in this regard just because it's the bible. You can't read passages about a man rising from the dead, curing blindness, and bringing the dead back to life without that little red flag going off in your mind that says 'this is more likely false than true. I'm going to need to see more evidence to back these claims'.
I don't care what you've been told by friends, family, and loved ones; and I especially don't care what you 'believe in your heart'... The original stories could be absolutely false, but if the myth took off and a few key people believed it, that's all it takes to explain how it got to where it is now.
Why are there no ancient critics?
What do you mean by 'ancient critics'? Do you mean first century people who said 'this is nonsense'? Isn't that basically everyone who didn't become a Christian?
There are probably multitudes of reasons that we don't see people speaking out against Christianity in the first century. The biggest one is probably because it started as a 'nothing' religion, just like all religions, and wasn't causing a big enough splash to say anything about. It wasn't this giant juggernaut from the beginning. It took 3 centuries to get big. It would be like you trying to figure out why there haven't been critics for every little cult that has ever springs up all over the world. You can sum up the entire criticism with a wave of the hand and a 'nah, that's not right'.
In the Bible record many Jews did not accept him as the Son of God. However, the did not reject that the miracles occured. They said "it's the devil", but they didn't deny they happened.
If you were the author of one of those gospels, and you wanted to make it look like this man was the son of God, and you wanted to explain why the Jews didn't buy it, isn't that exactly what you'd write too?
We have no idea who wrote the gospel stories, and half the letters attributed to Paul were not actually written by him. Why on earth do you think they are reliable?
Why iare there no outside (of Christianity) records to set things straight?
A bigger concern of yours should be the fact that there are no contemporary accounts of Jesus to verify the truth of it in the first place. You have to keep in mind that the gospels were written many years after Jesus died. Who is going to 'set the record straight' on events that took place decades earlier? Do you really think the people around Jerusalem, the vast majority of whom couldn't read or write to start with, would have bothered to learn to write, then pick up a pen and write down "No, I was there and none of that Jesus stuff happened"? Be serious now.
How did these similarities originate and is there any foundation of truth? It could be said that religious flood stories originated because of local flooding so there would be at least some grain of truth. On what grain of truth did belief in all these spirits originiate?
All myths, no matter how nutty, originate somewhere. Christianity is no different. The modern, American version of Santa Claus, as an example, is a myth that originated somehow. What 'grain of truth' lies behind it?