I am sorry, I am not going to wrangle with you. You are wrong on every point. You are reading something into the Galatians passage that is not there. When you read Gal. 2:7-9 you will see they intended not to duplicate efforts to the target audiences. The Gospel was the same for both, and their preaching did comprise both Jews and Gentile audiences. If I were you, I would look up every passage with the words 'apostle,' 'apostles,' and 'twelve' in the NT and see if you get a little depth.
I am sorry but Galatians 2:7-10 proves my point. If I were you I would study 2 Tim. 2:15 for the right way to study God’s Word of Truth. You are trying to force something to fit into your views that, if plainly read, would help in your understanding of this dispensation of the grace of God. Paul was not an afterthought. Nor was Matthias an accident. Unless you believe that God did not know what His Plan was for man.