Let's turn this around temporarily for the sake us who are not Orthodox. What is the basis for such teachings as:
Prayer To The Saints
Apostolic Succession
Ecumenical Councils as Infallible
Mary's Ever-Virginity and Bodily Assumption
and if a member rejects any of them, does it matter?
Won't be able to reply in detail. Maybe in few days.
None of these required fir sakvation, as far as I know.
The O Church DOES have beliefs not clearly articulated in Scripture. Shouldn't be a problem - even Scripture says hold to those teachings delivered by
word and epistle.
Asking intercession of Saints not required. Also not prohibited. Considered if it helps .... additional tool of benefit for us? But we believers are to pray for one another, in love. Christ intercedes for us. If believers are not unconscious, and are with Christ, the reasonable loving thing is to imitate and intercede for us?
Apostolic Succession - scriptural evidence of ordination. Records were kept. Men trained successors. Maybe more is implied than I know, but I think it just happened and was a reasonable course of action? Regarding todays's Christendom I think they could not foresee, but - like Antioch when believers were established, they sent Barnabas. B later went and got Paul. They stayed to teach for a year to establish Church. It seems normal process?
ECs ... I don't know if infallible is really right word, but the Church would be led into all Truth. Not one person only. So we trust what came to be accepted. Do you know a council can't teach against what the Church believes? Even laity have a place in maintaining doctrine. The reception of writings that became Scripture had to resound with laity to be accepted - an organic whole. Not some governing body that decides whatever it wants and must be obeyed.
Mary - from other writings and Tradition. Scripture doesn't actually contradict. Nevertheless harder for me to accept. But I do understand something now - relating to the miraculous connected to Christ instead. Seems very UNconnected to salvation though? Makes more sense too, to understand traditions associated with death of John, for example, and others, and realize some like Enoch, Elijah, Moses, ARE in Scripture. Funny, we defend miracles we read in Scripture, but reject those not mentioned, though John does specifically say not all of Christ's miracles written, so ... are we so sure every other miracle must be in canonized Scripture? Just my thinking though, but I found ironic.
Can we reject? Well, we must at least recognize the Church as having some authority. And as far as teaching about Mary, would have to talk to priest. I don't THINK it would bar communion ... but one would be censured for actively teaching against it. The only time I know of a person denied communion based on belief was doubt regarding the divinity of Christ. I'm speaking for those already Orthodox. If one wants to join and outright rejects these, the priest would probably hold off on receiving them. If they only have doubts though, it would depend, but disposed to Church's authority they could probably be received.
Hope that made sense. It's a big question.
We of course do not claim that everything we believe is explicit in Scripture, though most is supported or can be read as implied.