George Salmon in 1890 published a book entitled The Infallibility of the Church (University Press, Dublin)...even he states in regard to Gal 2:8:
"Paul limits Peter's province to the apostleship of the circumcision, that is to say, to the superintendence of the Jewish Churches; and states that the work of evangelizing the Gentiles had, b agreement with the three Chief Apostles, been specially committed to himself and Barnabus."
Within less than 20 years after Jesus' death, we see James acting as the first bishop of Jerusalem...where people are going to him for support/questions/judgment...
Acts 15:19: “It is my judgment... shows James giving directives to communities beyond as if it's THE authority of the church.
"James, who was surnamed 'The Just' by the forefathers on account of his superlative virtue, was the first to have been elected to the office of Bishop of the Jerusalem Church." ... Eusebius (263 to 339)
"The sixth book of Hypotyposes represents the following: Peter, James, and John after the Ascension of the Saviour, did not contend for the glory, even though they had previously been honoured by the Saviour, but chose james the Just as Bishop of Jerusalem." (Clement of Alexandria, 150 to 215)
There isn't any reason to believe that the roles were reversed in any way re: James & Peter.
Catholics have always recognized James as Bishop of Jerusalem. That’s exactly what I described: Peter sets the doctrine, and James implements it in his see.
As for you citations, you really should read something in its original context before you cite it. Your citation of Clement of Alexandria confuses the actual writings of Clement with another author’s citation of it. Clement of Alexandria actually cites Clement of Rome’s first epistle as “aposotolic,” even as if it were scripture itself. (The New Testament was still in a bit of a state of flux when Clement of Alexandria wrote.) In this first epistle, Clement of Rome affirms primacy over other sees. Now, our Eastern brethren disagree with the Catholic assertion that Clement of Rome’s primacy amounted to the authority of the papacy, but it certainly establishes that Peter’s see, not James’ see, was that of the primate.
In fact, time and time again throughout the New Testament, Peter is called “primus,” (first) when he was, in fact, *not* the first of the apostles. He *was* the first to witness the resurrected Christ, but only because John stopped and allowed him to enter first, a clear deference. And there are so many times when the other disciples ask Peter to ask Jesus something.