So I just lost the whoooooooooooole reply I wrote out to you because my computer is ridiculous, and it's really got me PO'ed. So this is going to be short.
In Acts 21-22 there is no confrontation between Paul and James so I still don't know what you're referring to. Paul's references to James in his epistles are all neutral or positive. Re: Paul saying he's a Roman citizen - I'm not seeing how that's evidence for a historical Jesus. And since you're referencing the book of Acts as evidence, why not just reference the Gospel of Luke (it certainly says there was a historical Jesus!) and call it a day?
Yes, Acts 21-22, where "Paul was warned by James and the elders that he was gaining a reputation for being
against the Law, saying 'they have been told about you that you teach all the Jews living among the gentiles to forsake Moses, and that you tell them not to circumcise their children or observe the customs.' "--Wikipedia article.
In Paul's own letters he also talks about it being OK to eat food sacrificed to idols, and I think worst of all, he institutes the Last Supper, as the consumption of Jesus' flesh and blood. That last even bothered many early church fathers because even the specific name for it, the Last Supper, was Mithraic. Also he claimed you didn't have to try to be good or do good works to be saved, only believe that Jesus died for our sins (human sacrifice). The Book of James, which is likely actually written by James, is pretty much reemphasizes all of this. Paul, and Luke, his apostle, had to face these issues because they were to well known, but they downplay them as much as possible.
The discovery of Paul's Roman citizenship (and thus his Herodian heritage) would have been the last straw for the Jews. Paul was under Roman house arrest for the next four years, waiting for trial, which occurrence isn't mentioned, and after which Paul comes off the stage of history. And the point of all this is that the historicity of Paul and James are not in dispute; and if they existed, Jesus had to have existed as well.
Re: the ossuary - it being original to the tomb does not demonstrate that it ever contained the bones of James the brother of Jesus Christ. The inscription on it is widely regarded as forged.
The evidence says otherwise. The primary witness for the forgery in the trial, Yuval Goren of the Israel Antiquities Authority, was so badly discredited the Judge openly questioned why the issue had even been brought to trial. Goren had to recant and admit that the patina inside the disputed part of the inscription was original. Experts from the Israel Geological Survey, have been almost exclusively against it being a forgery.
I've been following this particularly in Biblical Archaeology Review since the James ossuary issue first became public, and the evidence as well as the experts opinions have been overwhelmingly pro authenticity. As so often happens with evidence that's very involved, all the opposition has to say is that it's a lie, and the believers continue to believe.
It's a subscription site, but this is a link to the BAR article summarizing the James Ossuary information:
âBrother of Jesusâ Inscription Is Authentic! | The BAS Library