As for the rest of what you provided, in no instance ever did the example of Sts. Peter and Paul suffice to justify a schism or schismatical act.
Furthermore, what “evangelical truth” is supposed to be in jeopardy?
Are you suggesting that the SSPX are schismatics? The holy father, as far I can tell, has never declared such, so saying that or implying such would be calumny.
From my research, this is what the SSPX has brought to Rome’s attention that have appeared to been novelties put forth by the Second Vatican Council:
“All men are called to this Catholic unity which prefigures and promotes universal peace, and in different ways belong to it, or are related to it: The Catholic faithful, others who believe in Christ, and finally all mankind, called by God’s grace to salvation.” Lumen Gentium
**"It is an error in a matter of divine truth to imagine the Church as invisible, by which many Christian communities, although they differ from each other in theirfaith, are united by a bond that is invisible to the senses. Pope Pius XII
“There is but one universal Church of the faithful, outside which no one at all can be saved.” Lateran Council IV Pope Innocent III
“Faith in Christ cannot be maintained pure and unalloyed when it is not protected and supported by faith in the Church. Faith in Christ and faith in the Church stand together. If any man does not enter the Church, or if any man departs from her, he is far from the hope of life and salvation.” Pope Pius XI
“Heretics and schismatics are excluded from the Church because they have separated from her and belong to her only as deserters belong to the army from which they have deserted.” Catechism of Trent **
*“These Christians are indeed in some real way joined to us in the Holy Spirit for, by His gifts and graces, His sanctifying power is also active in them, and He has strengthened some of them even to the shedding of their blood.” Lumen Gentium *
**“The Catholic Church alone is the Body of Christ, of which He is Head and Savior. We must always remember the unity of the Mystical Body outside which there is no salvation; for their is no entering into salvation outside the Church. Truth, grace, the Sacraments: all the certain norms for our journey to God come from the Church. The Catholic Church is the extension of Jesus Christ in time and space. Outside this Body the Holy Spirit does not give life to anyone. Those who are enemies ot unity do not participate in the charity of divine life; those outside the Church do not possess the Holy Spirit. A Christian must fear nothing so much as to be separated from the Body of Christ. If he is separated from Christ’s Body, he is not one of His members; he is not fed by His Spirit.” Pope Paul VI
“If those unwilling to be at agreement in the Church be slain outside the Church, they cannot attain to the rewards fo the Church.” Pope Pelagius II
“No one, even if he pour out his blood for the name of Christ, can be saved unless he remain within the bosom and unity of the Catholic Church.” Council of Florence, Pope Eugene IV **
*“The Moslems together with us adore the one merciful God.” Lumen Gentium *
**“The Holy Catholic Church teaches that God cannot truly be adored except within its fold.” Pope St. Gregory the Great
“The Catholic Church alone preserves true worship.” Pope Pius XI
“A true worshipper is one whose mind has not been defiled with any false belief.” Pope St. Leo the Great **
No man can worship the one true God “together with us” if they do not share our one true faith. Islam teaches that Jesus is not God and that there is only one person in God; hence, they do not believe in the God we worship. Thus, they can in no way worship “with us” our God. A man cannot worship in any way that which he does not believe in, for the Law of Praying is the Law of Believing, and vice-versa. If they believe in a one-person deity, THAT is what they worship, and in no way “with us” can they worship the Holy Trinity, the Second Person of Which is a human being like us in all things but sin.
*“Those who, through no fault of their own, do not know the Gospel of Christ or of 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.” Lumen Gentium *
**“The saving grace of this religion, the only true religion, through which alone true salvation is truly promised, has never been refused to anyone who was worthy of it; and whoever did lack it was unworthy of it. Consequently, those who have not heard the Gospel, and those who, having heard it have not persevered; and those who, having heard it, have refused to come to Christ; that is, to believe in Him; ALL these have perished in death: the all go in a single lump to condemnation.” St. Augustine
“It is error to believe that there is a natural justice whereby eternal life is promised for good works without any further qualification.” Pope St. Pius V
“Acts which spring from natural goodness have only the appearance of virtue; they cannot last of themselves nor can they merit salvation.” Pope St. Pius X
“He who is separated from the Body of the Catholic Church, however praiseworthy his conduct may seem otherwise, will never enjoy eternal life.” Council of Cirta**
…more to follow…