The questions you pose are the big questions of the modern and post-modern era. Is there Salvation outside the Church, or for for dissenters within the Church?
On March 16, 2016, speaking publicly on a rare occasion, Pope Benedict XVI gave an interview in which he spoke of a “two-sided deep crisis” the Church is facing in the wake of the Second Vatican Council. I think his statement answers your question: the Church is deeply confused on this point and does not have a firm answer.
While the fathers and theologians of the Middle Ages could still be of the opinion that, essentially, the whole human race had become Catholic and that paganism existed now only on the margins, the discovery of the New World at the beginning of the modern era radically changed perspectives.
In the second half of the last century it has been fully affirmed the understanding that God cannot let go to perdition all the unbaptized and that even a purely natural happiness for them does not represent a real answer to the question of human existence.
If it is true that the great missionaries of the 16th century were still convinced that those who are not baptized are forever lost — and this explains their missionary commitment — in the Catholic Church after the Second Vatican Council that conviction was finally abandoned.
From this came a deep double crisis.
On the one hand this seems to remove any motivation for a future missionary commitment. Why should one try to convince the people to accept the Christian faith when they can be saved even without it?
But also for Christians an issue emerged: the obligatory nature of the faith and its way of life began to seem uncertain and problematic.
If there are those who can save themselves in other ways, it is not clear, in the final analysis, why the Christian himself is bound by the requirements of the Christian faith and its morals. If faith and salvation are no longer interdependent, faith itself become unmotivated.
Lately several attempts have been formulated in order to reconcile the universal necessity of the Christian faith with the opportunity to save oneself without it.
I will mention here two: first, the well-known thesis of the anonymous Christians of Karl Rahner. He sustains that the basic, essential act at the basis of Christian existence, decisive for salvation, in the transcendental structure of our consciousness, consists in the opening to the entirely Other, toward unity with God.
The Christian faith would in this view cause to rise to consciousness what is structural in man as such. So when a man accepts himself in his essential being, he fulfills the essence of being a Christian without knowing what it is in a conceptual way.
The Christian, therefore, coincides with the human and, in this sense, every man who accepts himself is a Christian even if he does not know it.
It is true that this theory is fascinating, but it reduces Christianity itself to a pure conscious presentation of what a human being is in himself and therefore overlooks the drama of change and renewal that is central to Christianity.
Even less acceptable is the solution proposed by the pluralistic theories of religion, for which all religions, each in their own way, would be ways of salvation and in this sense, in their effects must be considered equivalent.
The critique of religion of the kind exercised in the Old Testament, in the New Testament and in the early Church is essentially more realistic, more concrete and true in its examination of the various religions. Such a simplistic reception is not proportional to the magnitude of the issue.
Let us recall, lastly, above all Henri de Lubac and with him some other theologians who have reflected on the concept of vicarious substitution. For them the “pro-existence” (“being for”) of Christ would be an expression of the fundamental figure of the Christian life and of the Church as such.
It is possible to explain this “being for” in a somewhat more abstract way. It is important to mankind that there is truth in it, this is believed and practiced. That one suffers for it. That one loves. These realities penetrate with their light into the world as such and support it.
I think that in this present situation it becomes for us ever more clear what the Lord said to Abraham, that is, that 10 righteous would have been sufficient to save a city, but that it destroys itself if such a small number is not reached.
It is clear that we need to further reflect on the whole question.