Bwahahahahaha! The only thing Peter did in Rome was die. Maybe. Hehe Since they found the sarcophagus that can’t even be proven.
I think the idea of Peter being the first "Pope" of Roman Catholicism and that somehow "proving" Apostolic Succession is a far more important "fig leaf" for them than it is for us. There are MUCH more important differences than that. In your example following of James being the head of the church in Jerusalem while Peter was definitely NOT in charge and presiding over the council, pretty blatantly proves Peter was NOT the head of the church. But also, the many times in Scripture where James is called the Lord's brother, why wouldn't THIS be the Catholics other fig leaf - that stripped away leaves THEM naked - because it proves Mary had more children than just Jesus? Therefore, her "perpetual" virginity would have to be acknowledged as false leaving the Catholics with yet another "infallible" doctrine stripped away.
I wish these two areas were the only ones with which we part ways. That they follow an accursed Gospel is what bothers me the most. Nobody will go to hell based on what they do or don't believe about Peter OR about Mary's perpetual virginity, but no one can be saved who relies on their own merit and works to save them. It is by God's grace NOT of our works that we are saved and to really trust in Christ and believe on his name means letting go of the idea that we can do anything to earn our forgiveness or pay the penalty of our sins.