I don’t have time to respond to all of the points right now, but wanted to address one that I recently posted about in another thread.
First though, I would point out that based on several of the questions it appears your friend is suffering from what I call “protestant either/or -ism,” where, because the Bible says one thing, it is interpreted as being to the exclusion to everything else when such a reading is simply not present in the text. For example, take question #3. While 1 Peter 2 does present the teaching of the concept of the priesthood of all believers, no where does it say that there is not also a ministerial priesthood passed on through the laying on of hands. In fact we see that there is such a ministerial priesthood in other verses, e.g. 1 Tim. 4:14, 5:22. That is the problem with “proof texting” where a passage is taken out of context and not considered in light of the whole revelation of scripture. Therefore, I would submit that the better approach is the Catholic “both/and” approach. We believe in both the priesthood of all believers and the ministerial priesthood. We believe in both baptism by immersion and by pouring/sprinkling. We believe in both that Christ is the one mediator and that He shares that mediator role with the angels and saints in heaven and on earth through intercessory prayer for one another (which the Bible explicitly instructs us to pray for one another, e.g. James 5:16, in itself a type of mediation). I think this approach is more true to the overall meaning of the entire text.
As to #12, I addressed this recently in another post:
If we look at the entire discourse instead of stopping at verse 27, we see that Jesus singles out St. Peter as the leader of the apostles in this discourse:
First, looking at verses 25-27 we can see that the “among you it shall not be so” does not mean that there will not be a leader of the apostles as Jesus clearly speaks of “the leader” using the definite article. This indicates that there is indeed to be a leader among the apostles. What Jesus is saying is not that there is to be no leader of the apostles, but that the one who is the leader will not “lord it over them.” Rather this leader is to be “as the servant,” just as Jesus, who is clearly the leader of His apostles, is “among [them] as the one who serves.” We see Jesus put this exhortation in to action in John 13:1-17 when He washes the disciples’ feet (both the speech in Luke and the washing of the feet in John occur at the last supper).
Next, in verses 28-30, Jesus confers on the twelve a share in His kingdom, placing them in positions of authority to judge “the twelve tribes of Israel” (which under the New Covenant includes both Jew and Gentile). Finally, in verses 31 and 31, after having conferred His kingdom on all of the apostles, Jesus singles out Peter and instructs him to strengthen his brothers in the face of the coming attacks from the devil. This instruction to “strengthen your brothers” is clearly a servant role. Peter, as the leader of the apostles, is to serve the other apostles by strengthening them. We see this in action down to today in the papal office. This is why one of the Pope’s titles is “Servant of the Servants of God.”