I disagree with you concerning biblical canonicity. The RCC had their own way of determining which writings would be included but then early church father's such as Irenaeus, Origen, and others already had specific rules to judge which writings should be included and which should not. The canon was already in existence before 312 A.D. which is official beginning of the RCC under Constantine.
And by the way, there is a sticking point where we'll always disagree and is at the heart of what many people from many denominations consider heresy. Church history is very important to study and remember for just the reasons we just cited, e.g., for determining the Canon of Scriptures , but our definition of "handed-down Apostolic teaching" is the rub. The Bible already gives us all the Apostolic teaching we need. Nowhere in scripture is there any handing down of any kind of this type of authority. You base your beliefs on an incorrect rendering of Christ's words which say upon Peter He would build His church. But it was upon Peter's confession of Him as Lord that was the "foundation."
Many "protestant" denominations such as the ECUSA, and Anglicanism, for example, yield greatly to church history and tradition, and rightly so. However, they do not place these important tenants above Holy Scripture. The ONLY person who can enlighten us about the interpretation and right use of the Word of God is the Holy Spirit Himself, and no other, not Pope, Bishop, Priest, or anyone.
1. Your claim that "the canon was already in existence before 312 A.D." doesn't reflect reality. If the canon of Scripture was clearly settled by 312 A.D. there would have been no need for subsequent definitions of the canon. Yet in different areas different canons were used as late as the fourth century, and different canons persist even today. Because of the ongoing controversy the Council of Hippo under Pope Damasus I defined the canon in 382 A.D., and the same canon has been reiterated by subsequent popes and councils: even after the Protestant Reformers adopted a different canon.
2. Your claim that "the Bible already gives us all the Apostolic teaching we need" ironically is unsupported by Scripture. No passage -no, not even 2 Timothy 3- makes any claim that Scipture alone contains "all the apostolic teaching we need". That's a Protestant invention.
3. Many Protestants claim that Matthew 16:18 does not say what it clearly says: that Jesus was giving Simon the name "rock", and that upon this "rock" He would build His Church. But it does plainly say that. Elsewhere in Scripture we are told that the apostles are the "foundation" of the Church (Revelation 21:14). And we are told that believers are "living stones", and that we form a "spiritual edifice" (1 Peter 2). And Jesus is the "cornerstone". Elsewhere Jesus is called the "capstone" (Ephesians 2:20). It's unfortunate that Protestants fight so hard against the plain meaning of the passage. So, no, Peter's not God; he's not perfect; he's not all-knowing; he's not sinless. But he is the "rock" that Jesus picked to serve in some sense as the foundation of His Church.
4. You said, "Nowhere in scripture is there any handing down of any kind of this type of authority." You need to go back and do some more reading. There is abundant evidence that Jesus gave the apostles authority that was then given to other men by means of "handing down": from the Greek "paradosis", and the Latin "traditio". English: "tradition". Paul spoke of it a great deal with Timothy, and elsewhere. And in Acts we see the apostles (under Peter's guidance) clearly aware that Judas' "office" was vacant and his "place" needed to be filled: so they elected Matthias to this ministry. Homework for you: find the passage in Paul's writings where he refers to five (five!) successive generations of apostolic authority.
5. The RCC specifically denies that it places tradition "above Holy Scripture", and I also deny it. You can't legitimately separate Scripture and apostolic tradition.
Finally, You say "The ONLY person who can enlighten us about the interpretation and right use of the Word of God is the Holy Spirit Himself, and no other..." If that is so, why are we having this discussion? If we Christians are not to listen to each other about the Word of Life, then why should I listen to you? And if I listen to you, how much more should I listen to those who have been appointed teachers in the Church, and who are in union with those who have received apostolic authority?
God bless you, Josie.