I think you did pretty good until you got to the last three paragraphs on invincible ignorance, you might want to study up a little more on that, especially that last sentance.
CCC 846 How are we to understand this affirmation, often repeated by the Church Fathers? Re-formulated positively, it means that
all salvation comes from Christ the Head through the Church which is his Body:
Basing itself on Scripture and Tradition, the Council teaches that the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and Baptism, and thereby affirmed at the same time the necessity of the Church which men enter through Baptism as through a door.
Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.
CCC 847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.
Leaving aside invincible ignorance the highlighted parts clearly show that salvation is only from Christ through the Catholic Church and those who leave it or refuse to enter it will not be saved.
Obviously Buddhists, Hindus, Muslims and those of other non-Christian religions have rejected Christ and so will not be saved. Everyone who rejects Christ and his Church will not be saved.
Slightly more tricky when it comes to Protestants. They believe Christ is our only salvation and they have some of the truth but only the fullness of truth is found in the Catholic Church. Those Protestants who have looked at and investigated the Catholic Church and have rejected it I believe unless they repent before death they be not be saved.
I’m not so clear on Protestants who have not condemned the Catholic Church nor explored it to see if it has the fullness of truth but were simply born and brought up Methodists, Anglicans or whatever and simply accepted their lot.
As for invincible ignorance I would stand my ground and say there cannot be many who would fall into this category. How many do you think have never heard of Christ and the Church he established?