Yes.
Dion is working from the precept that one cannot be held accountable for what one does not know (Jesus said to them, "If you were blind, you would have no guilt; but now that you say, 'We see,' your guilt remains. John 9:41) while Hermann is working from the precept that ignorance of truth is always a negative position (" My people are perishing from a lack of knowledge," Hosea 4:6). Both of these precepts belong to the faith, so the question is how to reconcile the two?
Well, I think it has more to do with this. Membership in the Catholic Church is necessary for salvation by a necessity of precept and by a necessity of means. A necessity of precept means that it has been commanded by God under pain of mortal sin. A necessity of means is when something has been established by God as the only means of attaining an end, in this case, salvation. Because of this double necessity which is contained in the doctrine "extra ecclesiam nulla salus," not only one will be condemned if he knowingly refuses to join the Church; he who does not join her because he is vincibly ignorant of the truth of her claims is also rejected.
Invincible ignorance does not create an exception, but those who are invincibly ignorant can belong to the Church by desire if they have true supernatural charity, and would submit to the Church if only they were not hindered by whatever reason from discovering the truth. This is well expressed in the Protocol Letter of the Holy Office to Archbishop Cushing; but Dion seems to reduce the Church's necessity for salvation to a necessity of precept only; or he speaks very unguardedly.
http://www.ewtn.com/library/CURIA/CDFFEENY.HTMNow, among the commandments of Christ, that one holds not the least place by which we are commanded to be incorporated by baptism into the Mystical Body of Christ, which is the Church, and to remain united to Christ and to His Vicar, through whom He Himself in a visible manner governs the Church on earth.
Therefore, no one will be saved who, knowing the Church to have been divinely established by Christ, nevertheless refuses to submit to the Church or withholds obedience from the Roman Pontiff, the Vicar of Christ on earth.
Not only did the Savior command that all nations should enter the Church, but He also decreed the Church to be a means of salvation without which no one can enter the kingdom of eternal glory.
In His infinite mercy God has willed that the effects, necessary for one to be saved, of those helps to salvation which are directed toward man's final end, not by intrinsic necessity, but only by divine institution, can also be obtained in certain circumstances when those helps are used only in desire and longing. This we see clearly stated in the Sacred Council of Trent, both in reference to the sacrament of regeneration and in reference to the sacrament of penance (Denzinger, nn. 797, 807).
The same in its own degree must be asserted of the Church, in as far as she is the general help to salvation. Therefore, that one may obtain eternal salvation, it is not always required that he be incorporated into the Church actually as a member, but it is necessary that at least he be united to her by desire and longing.
However, this desire need not always be explicit, as it is in catechumens; but when a person is involved in invincible ignorance God accepts also an implicit desire, so called because it is included in that good disposition of soul whereby a person wishes his will to be conformed to the will of God.
These things are clearly taught in that dogmatic letter which was issued by the Sovereign Pontiff, Pope Pius XII, on June 29, 1943, On the Mystical Body of Jesus Christ (AAS, Vol. 35, an. 1943, p. 193 ff.). For in this letter the Sovereign Pontiff clearly distinguishes between those who are actually incorporated into the Church as members, and those who are united to the Church only by desire.
Discussing the members of which the Mystical Body is-composed here on earth, the same august Pontiff says: "Actually only those are to be included as members of the Church who have been baptized and profess the true faith, and who have not been so unfortunate as to separate themselves from the unity of the Body, or been excluded by legitimate authority for grave faults committed."
Toward the end of this same encyclical letter, when most affectionately inviting to unity those who do not belong to the body of the Catholic Church, he mentions those who "are related to the Mystical Body of the Redeemer by a certain unconscious yearning and desire," and these he by no means excludes from eternal salvation, but on the other hand states that they are in a condition "in which they cannot be sure of their salvation" since "they still remain deprived of those many heavenly gifts and helps which can only be enjoyed in the Catholic Church" (AAS, 1. c., p. 243). With these wise words he reproves both those who exclude from eternal salvation all united to the Church only by implicit desire, and those who falsely assert that men can be saved equally well in every religion (cf. Pope Pius IX, Allocution, Singulari quadam, in Denzinger, n. 1641 ff.; also Pope Pius IX in the encyclical letter, Quanto conficiamur moerore, in Denzinger, n. 1677).
But it must not be thought that any kind of desire of entering the Church suffices that one may be saved. It is necessary that the desire by which one is related to the Church be animated by perfect charity. Nor can an implicit desire produce its effect, unless a person has supernatural faith: "For he who comes to God must believe that God exists and is a rewarder of those who seek Him" (Heb. 11:6). The Council of Trent declares (Session VI, chap. 8): "Faith is the beginning of man's salvation, the foundation and root of all justification, without which it is impossible to please God and attain to the fellowship of His children" (Denzinger, n. 801).