There's a lot here. My response, I should be clear, is mine. I can't speak for all Christians, nor do I want to try. Some Christians adopt views that I, as a Christian, find extremely problematic (such as a literalist reading of Genesis).
The first point I want to make is that I am not one who believes that an individual can be argued into (any) faith. That's precisely why it's called faith - there comes a point where one has to bridge a gap and accept, "I can't explain every detail, but I believe." Now, I recognize that that answer can be taken as a cop-out, and I don't mean it as such. I'm not saying that faith should be logically inconsistent or irrational - my approach is that faith needs to be as consistent and rational as possible. However, it would be a mistake to think that it can be entirely either. After all, if God (or Allah or YWHW or any other name given to a higher power by any religion) is completely within human ability to comprehend, then God is not worthy of worship. Faith and mystery interact in all religions, whether they admit it or not.
As far as your numbered responses:
1-2. No one should be forced to accept the claims of any religion. Period. The test of the validity of any claim to reality is dependent on several factors. For my theological tradition (Methodism - the school of thought founded by John Wesley), we approach the test of validity through four lenses. Scripture - this is the most important and foundational question - is it consistent with the overall message of the story of God's people; Reason - does it make sense within the framework of a Christian worldview; Experience - does it fit with my experience and the experience of others; and Tradition - how does it approach what the Church (big "C," meaning the whole of Christian faith over the centuries) has always lived and taught. That's how we approach it from within the system.
When discussing with someone who approaches faith from the outside, we have to define our foundational assumptions, which form the basis for our worldview. In a nutshell, those foundational assumptions are defined in the Nicene Creed. I usually boil them down to: There is a God who created (however we understand creation); God is love; God's love ultimately wins. Now, I cannot conclusively prove the existence of God (any more than one could conclusively disprove the existence of God). If one is not willing to grant the existence (or at least the possibility of the existence) of God, then all reality claims between that individual and a Christian become moot. And that's okay - again, no one should be forced to accept the claims of any religion.
3. The way the books of the Bible were "chosen" relied on several lines of thought. The closer to the time of Jesus a book was written, the more likely it was to be included. If a book was written by someone famous in the church - like a disciple or someone like Paul - it was more likely to be included. The most important test, though, was extent of use. That is, if a book was widely used by churches throughout the known world (Roman Empire), it was more likely to be included. Matthew, Mark, Luke and John were all written in or right at the end of the first century, and were widely known and used in the early church, so they were included as "orthodox." The Gospel of Thomas and the Gospel of Judas and others were not widely used and were written much later. It's not a perfect system by any means, but it goes deeper than "if it's old, it's true."
4. It's not as clear as you might think. Christian theologians have argued for centuries that God will ultimately "save" everyone, and there are some Scripture verses that seem to take that approach. It's too much to try to get into in detail in this post, but the idea of universalism is present in both Christian theology and Jewish theology.
5. You are right that there are other stories of "Jesus"-like figures that predate the Bible. However, there is something to be said for the fact that the stories of Jesus have endured for 2000 years and retained their power and influence. Others have not. The enduring impact of these stories speaks to a long tradition of credibility. I also find compelling the argument that the early Christians - Peter, Paul, etc. - who died because of their faith in Jesus would not have endured what they endured if they had known the stories of Jesus were definitely false.
These are not perfect answers - I don't know that perfect answers exist to your questions. I hope that maybe I was able to provide a little food for thought. Thanks for challenging me to think through some of these things again.
Great post, it's refreshing to see that you've thought through these various aspects of your faith very thoroughly...not surprising given that you're a pastor but nonetheless it's still good to see.
I didn't take your initial "faith" answer as a copout. In fact if I ever speak to anyone about religion from a more "evidence-based standpoint" and they simply say, "look I realize some of my beliefs are faith-based", then I'm fine with that. I don't personally have faith for things outside of observation, but I don't hold it against others if they want to. Where I tend to be more "argumentative" for lack of a better word is if someone denies that faith is even a necessary component of their religion, e.g. if they claim to have a fully evidence-based and logical approach to what their religion teaches and so forth. Religion does require faith, precisely because there are parts that can't be "proven" per se.
Regarding point 4, I'm not sure I can agree how credibly one should take this notion of "universalism" though. What I mean is the Christian Bible does have some verses that point in the "everyone will get saved" direction, but as you know there are hundreds more verses that really lay a stake in the ground about exactly what needs to be believed and the consequences if that doesn't happen. I would expect some overlap with Jewish Faith here. But I don't think there's nearly as much "wiggle room" or "overlap" when it comes to some other large religions. Either way to be honest this one does feel like a "convenient out" in some ways to believe in universal salvation. The very reason holy wars happen (and are happening today, are these substantial differences. Universalism also feels like it minimizes the importance of following a religion's precepts in order to be saved, if pretty much everyone is getting saved anyway. I think those who TRULY believe in both God and universalism are the ones who watch football on Sundays instead of going to church. I know you saved some details for brevity but I just wanted to comment on that.
Regarding similar stories predating Jesus, I'm not sure how many others have but the Hindu deity Krishna has survived the test of time as well. I believe he originated several centuries before Jesus. And similar to Jesus, Krishna was born of divine conception, healed the sick, raised the dead, etc. A Hindu friend of mine tells me Krishna could take Jesus in a cage match because Krishna has better "powers" such as being able to take many forms at once and lift mountains. Not sure if he's right about that or not haha.
And to @Boilermaker, that's right, Boiler Up!!