The OO Church does not believe in salvation for heretics or schismatics, but does not judge believers who sin based on their weak nature. This has been the position of the Church since the Apostles and has been explained many times by the Fathers throughout history. Maybe you need to consult them instead of embracing a false ecumenical spirit. I want to emphasize the quote of St. Ignatius that stresses on using one Eucharist, and who speaks the mind of the Apostles, and the famous quote by St. Cyprian that there is no salvation outside the Church.
I shall not argue this point (salvation and consequently sainthood outside the church) anymore, but I shall come back to discuss some points made as relevant to the OO church.
Ignatius of Antioch
"Be not deceived, my brethren: If anyone follows a maker of schism [i.e., is a schismatic], he does not inherit the kingdom of God; if anyone walks in strange doctrine [i.e., is a heretic], he has no part in the Passion [of Christ]. Take care, then, to use one Eucharist, so that whatever you do, you do according to God: For there is one flesh of our Lord Jesus Christ, and one cup in the union of his blood; one altar, as there is one bishop, with the presbytery and my fellow servants, the deacons" (Letter to the Philadelphians 3:3-4:1 [A.D. 110]) .
Irenaeus of Lyons
"In the Church God has placed apostles, prophets, teachers, and every other working of the Spirit, of whom none of those are sharers who do not conform to the Church, but who defraud themselves of life by an evil mind and even worse way of acting. Where the Church is, there is the Spirit of God; where the Spirit of God is, there is the Church and all grace" (Against Heresies 3:24:1 [A.D. 189])
Irenaeus of Lyons
"[The spiritual man] shall also judge those who give rise to schisms, who are destitute of the love of God, and who look to their own special advantage rather than to the unity of the Church; and who for trifling reasons, or any kind of reason which occurs to them, cut in pieces and divide the great and glorious body of Christ, and so far as in them lies, destroy it--men who prate of peace while they give rise to war, and do in truth strain out a gnat, but swallow a camel. For they can bring about no 'Reformation' of enough importance to compensate for the evil arising from their schism. . . . True knowledge is that which consists in the doctrine of the apostles, and the ancient constitution of the Church throughout all the world, and the distinctive manifestation of the body of Christ according to the successions of the bishops, by which they have handed down that Church which exists in every place [i.e., the Catholic Church]" (ibid., 4:33:7-8) .
Cyprian of Carthage
"Whoever is separated from the Church and is joined to an adulteress [a schismatic church] is separated from the promises of the Church, nor will he that forsakes the Church of Christ attain to the rewards of Christ. He is an alien, a worldling, and an enemy. He cannot have God for his Father who has not the Church for his mother" (The Unity of the Catholic Church 6, 1st ed. [A.D. 251]) .
Cyprian of Carthage
"Let them not think that the way of life or salvation exists for them, if they have refused to obey the bishops and priests, since the Lord says in the book of Deuteronomy: `And any man who has the insolence to refuse to listen to the priest or judge, whoever he may be in those days, that man shall die' [Deut. 17:12-13]. And then, indeed, they were killed with the sword . . . but now the proud and insolent are killed with the sword of the Spirit, when they are cast out from the Church. For they cannot live outside, since there is only one house of God, and there can be no salvation for anyone except in the Church" (Letters 61:4 [A.D. 253]) .
Cyprian of Carthage
"[T]he baptism of public witness [desire] and of blood cannot profit a heretic unto salvation, because there is no salvation outside the Church." (Letters 72:21 [A.D. 253]) .
"It is, therefore, the Catholic Church alone which retains true worship. This is the fountain of truth; this, the domicile of faith; this, the temple of God. Whoever does not enter there or whoever does not go out from there, he is a stranger to the hope of life and salvation. . . . Because, however, all the various groups of heretics are confident that they are the Christians and think that theirs is the Catholic Church, let it be known that this is the true Church, in which there is confession and penance and which takes a health-promoting care of the sins and wounds to which the weak flesh is subject" (Divine Institutes 4:30:11-13 [A.D. 307]) .
"Heretics bring sentence upon themselves since they by their own choice withdraw from the Church, a withdrawal which, since they are aware of it, constitutes damnation. Between heresy and schism there is this difference: that heresy involves perverse doctrine, while schism separates one from the Church on account of disagreement with the bishop. Nevertheless, there is no schism which does not trump up a heresy to justify its departure from the Church" (Commentary on Titus 3:10-11 [A.D. 386]) .
"We believe also in the holy Church, that is, the Catholic Church. For heretics violate the faith itself by a false opinion about God; schismatics, however, withdraw from fraternal love by hostile separations, although they believe the same things we do. Consequently, neither heretics nor schismatics belong to the Catholic Church; not heretics, because the Church loves God; and not schismatics, because the Church loves neighbor" (Faith and the Creed 10:21 [A.D. 393]).
"Whoever is separated from this Catholic Church, by this single sin of being separated from the unity of Christ, no matter how estimable a life he may imagine he is living, shall not have life, but the wrath of God rests upon him" ((Faith and the Creed 10:21)