Re 11, why does it matter how far back the tradition went ? Paul was the Apostle to the Gentiles, and whatever tradition he taught the you can rely on. The issue is what traditions did he teach that are not recorded in his surviving writings, and how can we know.
"According to Paul, the spoken words of the apostles were the word of God. In fact, when Paul wrote his second letter to the Thessalonians, he urged Christians there to receive the oral and written Traditions as equally authoritative. This would be expected because both are the word of God:"
Tradition is being masde equal to The Word of God and I don't think that is what Paul is saying.