I'm curious how you interpret John 20:21-23:
"He said therefore to them again: Peace be to you. As the Father hath sent me, I also send you. 22 When he had said this, he breathed on them; and he said to them: Receive ye the Holy Ghost. 23 Whose sins you shall forgive, they are forgiven them: and whose sins you shall retain, they are retained."
That seems fairly clear that Christ instituted the sacrament of Penance. Is there another way to interpret it?
prayers to dead saints
Just to be clear, the Church does not require the faithful to ask for the intercession of the Saints - it is encouraged, but in no way required.
baptism into the Catholic Church
The Church recognizes all baptisms done in the name of the Father, the Son, and the Holy Spirit as valid baptisms into the Body of Christ.
But the Holy Spirit was passed on to others when they were baptized. Oh, I think you mean to ask about verse 23. This is the keys to the kingdom as before, which is the gospel message itself. It was Jesus' payment for our penalties that forgave all our sins, but we still had to hear it before we could accept that forgiveness. The message has power and refusing it to someone was up to them.
The Church recognizes all baptisms done in the name of the Father, the Son, and the Holy Spirit as valid baptisms into the Body of Christ.
Really. I heard differently, and that it was to such a point that Communion (Eucharist?) is refused to those baptized in Protestant denominations.
"He said therefore to them again: Peace be to you. As the Father hath sent me, I also send you. 22 When he had said this, he breathed on them; and he said to them: Receive ye the Holy Ghost. 23 Whose sins you shall forgive, they are forgiven them: and whose sins you shall retain, they are retained."
On what basis do you believe that the supernatural powers given to the Apostles were passed on?