I suppose the "RC church" means the Roman Catholic Church. Being of the Byzantine Rite, I find "Catholic Church" to be a better, as well as the more correct, descriptor. "Roman Catholic" means primarily the local Church at Rome, whose Bishop is the successor of St. Peter and therefore the visible head of the Catholic Church. Secondarily, it indicates Catholics who practice their Faith by the laws, customs, and Liturgy of the Latin Rite of the Church. These things develop and change over time - not the Faith!
The Catholic Church believes and teaches that She is the One Church founded by Jesus Christ upon His 12 Apostles with the promise of Divine protection and mission to proclaim the Gospel of Christ to the whole of Creation in it's fullness and entirety, leading Creation back to God. She is at once the mystical Body of Christ and His Bride. Christ is Her Head and the Holy Spirit Her Soul. She therefore can only but claim for Herself alone the ability to preach the Gospel in it's fullness and entirety of Divine Truth with no error. She, by Christ's will, also is given the ability to mediate Grace to us through the Sacraments, which are Christ's way of applying the fruits of His Redemption to us all through the ages.
She teaches that all are called to live in the Truth. Because Christ is united to Her such that He identifies Himself with Her, "Saul, Saul why do you persecute Me", and all Salvation comes to the world through Him, all people are obligated to be baptized in Her for Salvation upon discovery that She is God's Church (as well as Christ's explicit command in the Gospels). All are called to believe Her teachings, led and protected by the Holy Spirit, which must be without error. Otherwise, Christ would be a liar, and therefore not God, and Christianity a big waste of time.
While the Church Herself, which St. Paul finally "broke down" and called "a Mystery" after describing by analogy after analogy Her character, is spotless in Her Head Who is Christ, this is not true of the individuals here on Earth who constitute Her. Quite frankly, we are all sinners, who continue to struggle time and time again to keep from sinning, and, turning from God's Grace, sin again and again. Fortunately, if we keep getting back up to respond to His Grace and forgiveness, we hopefully continue to grow ever more closer to God. The Catholic Church does not teach that all Catholics automatically will go to heaven. They must strive to live in Grace wrought by the Redemption of Christ.
What about non-Catholics? Our separated brethren in other Christian communities such as the Orthodox, who have the same Faith as Catholics, and Protestants, who variously run the gamut of different additions, subtractions, and changes of the pure Faith given by Christ? What about those who don't believe in Christ at all?
It is a shame in the world today that Christianity is split up, making a mockery of Christ's Priestly prayer of unity in the Gospel of St. John. We Catholics see our separated Christian brethren as just that - separated Christian brethren. We recognize and share large stretches of our Faith together which overwhelms our various disputes. To the extent that we agree, Catholics recognize the Grace of God at work in our separated brethen - and others as well. Through the Holy Spirit, we Catholics know that full unity is obtainable and by the command of Christ should desire and work for this.
The Catholic Church teaches that all Salvation comes through Christ and therefore through Her - which is why He established Her in the first place. We believe that individuals, who through no fault of their own, do not belong to Her can be saved. This includes non-Christians. This does NOT mean that Salvation occurs without Christ. It means that in His mysterious ways He can always find ways to save people, defeating Satan. God wills that all men and women to be saved, "Your will be done...". This Salvation comes through Christ and is necessarily connected to His Church. Nobody is authorized by God to say who will and who won't be saved - that Judgement belongs to God alone.
As far as your question on whether or not can somebody be saved who doesn't hold all the teachings of the Church - well, I hope so! Not everybody is a theologian and, let's face it, among Catholics, Orthodox, and Protestants alike, there are some weird and screwy understandings of the Faith and Scripture out there. There is a lot of ignorance as well. Think, do I know more about my Faith today than I did 5 years ago? Indeed, in the Middle Ages, there were theologians in the Church who, in terms of developing an understanding of the Faith with reason through the science of Theology, called into question the Immaculate Conception of Mary for a variety of reasons, not least of which are shared in a general way by many Protestants. This was the result of a normal development of the Church growing into a deeper understanding of the gift of Revelation given by God. Understand, the teaching had always been believed and celebrated in the Liturgies of both the East and West since the earliest Centuries. Understanding and applying how that teaching affected the lives of Christians was at stake. This is true for all the teachings of the Church. While nothing in Divine Revelation may be added, deleted, or changed, our understanding can, and is meant to, grow through the ages.
Incorrect. Absolutely incorrect. I have found far more in common with Rnmom and Hank Kerchief, than I have with any Catholic here on FR. I prefer to be lumped with the protestants, thank you.
We have a firm base in Holy Scripture, belief in and support of individual communion with God ( our priests are *not* mediators), no authority of the church as the Catholics view it - the church for us is the people rather than an earthly and transient institution, no papism or infallible humans, no purgatory or Marianism, and many more commonalities with the Protestants.
Catholic Guy recently elaborated quite well on this topic. He said in another thread, "You guys are protestants" to an Orthodox Christian.