I love you as a brother. I admire your intellect and knowledge. I admire your zeal for the Faith. I admire your concern for the souls of those not Christian Catholic.
Nevertheless, you ought be more humble is thinking your explanations of Catholic Dogma and Doctrine is definitive.
Catholic Catechism
817 In fact, "in this one and only Church of God from its very beginnings there arose certain rifts, which the Apostle strongly censures as damnable. But in subsequent centuries much more serious dissensions appeared and large communities became separated from full communion with the Catholic Church - for which, often enough, men of both sides were to blame."269 The ruptures that wound the unity of Christ's Body - here we must distinguish heresy, apostasy, and schism270 - do not occur without human sin:
Where there are sins, there are also divisions, schisms, heresies, and disputes. Where there is virtue, however, there also are harmony and unity, from which arise the one heart and one soul of all believers.271
818 "However, one cannot charge with the sin of the separation those who at present are born into these communities [that resulted from such separation] and in them are brought up in the faith of Christ, and the Catholic Church accepts them with respect and affection as brothers . . . . All who have been justified by faith in Baptism are incorporated into Christ; they therefore have a right to be called Christians, and with good reason are accepted as brothers in the Lord by the children of the Catholic Church."272
819 "Furthermore, many elements of sanctification and of truth"273 are found outside the visible confines of the Catholic Church: "the written Word of God; the life of grace; faith, hope, and charity, with the other interior gifts of the Holy Spirit, as well as visible elements."274 Christ's Spirit uses these Churches and ecclesial communities as means of salvation, whose power derives from the fullness of grace and truth that Christ has entrusted to the Catholic Church. All these blessings come from Christ and lead to him,275 and are in themselves calls to "Catholic unity."276
Perhaps I was a uniquely tortured Protestant soul in my 10 years of youthful wrestling with the question of why I was not a Catholic. That is always possible.
But after talking to other Protestants, I think not.
Its near impossible to be conscious of the Christian faith and not question why one is not a Catholic, and what particular Catholic doctrines one disbelieves, especially in a land like the US where there are Catholics everywhere, the Pope and Bishops are constantly in the news, etc. Its not like the Catholic Faith is hidden away from everyone in America and Europe as some obscure underground sect like in China.
The other problem in this whole line of thought about the salvific wonders of Protestantism is the casual acceptance by most Protestants of crimes against the natural law(contraception, divorce and remarriage, fornication, pornography, abortion, heterosexual sodomy, homosexuality, harpy-feminism, test-tube babies, non-obligation of regular worship of God, mistreatment of parents in their dottage, etc.).
The natural law is not a matter of ignorance vincible or invincible, since it is written upon everyone's heart.
To discover sanctity as a non-Catholic, normally one must first come to an acceptance of the natural law, and then God will begin to reveal Himself to the struggling sinner of docile mind and good will, certainly using the means at hand of the mistaken worship of Protestantism.