Fortunately, there’s a bit more evidence on the table in the form of oral and written testimonials, art objects, and buildings dedicated in his name.

Only contemporary first hand evidence. Not what some zealots said nine centuries later.

f we’re crediting the Gospel of James as a credible record of an individual’s existence, I’m hard pressed to dismiss the Gospels of Mark and Luke, which are older and at least as credible.

No. I am crediting Paul since I can’t see why on earth he would make up a character like James, I am crediting the Gospel of Thomas as predating Mark and mentioning him, I am also pointing out that we can see traces of his impact in John. I don’t need the Gospel of James. Btw Luke just copied Matthew and Matthew just coped Mark.

So we’re putting all our chips on “A particular popular rabbi with a large following never got on top of a hill and held a sermon in front of an audience that failed to bring enough food along for lunch”?

I don’t think the man existed. And even if he had existed and gave that speech I think you are ignoring the fact that the miracle is clearly a reference to the OT story about food multiplication. It isn’t that it is impossible to have happened it is there is an easier way to explain where the story came from. Imagine a thousand years from now someone like you is arguing for Spiderman and saying “isn’t it possible someone could swing around the city”. “Sure but the people at that time had a story about a superhero who could do that so that is where it probably came from”.

Of all the various parables and miraculous events attributed in the New Testament, I would consider “Guy gives speech to large hungry crowd and then feeds them” one of the least controversial.

Cool? None of them happened. Every single miracle he performs we can trace back to the literature that existed at the time.