[...continued from my last post]
Prove all things; hold fast that which is good. (1 Thessalonians 5:21)
You asked if the litmus test for an Orthodox church/jurisdiction to be worthy of the name was an adherence to the Old Calendar and a rejection of Ecumenism. No. I used to think this way, after carefully studying the "calendar question" and concluding that the "Old Calendarists" have it right. I learned the hard way that there is more to true Orthodoxy than meeting these two criteria...
I came into contact, and even intimate spiritual influence, with a small group out of Colorado, led by a man named Gregory. I was impressed by their writings: they were hard-line anti-Ecumenists, they followed the Old Calendar, the way they walked, talked - everything about them seemed right.
Except they had been excommunicated by their synod, their leaders. They had broken Canon law. They were not a part of the Church.
So this is where I'm going to start answering, the best I can, some of the questions you have. I will try to guide you to the resources I used to make a reasonable conclusion. And I truly believe, if you are truly searching, truly asking, that God will guide you into the truth. So let's get started.
You asked: "What Canons and when were these Canons established? Are these Canons the equivalent to what the Catholic Church calls the Canon Law?"
These: The Canons of the Apostles
And these: The Seven Ecumenical Councils and their Canons.
These canons were established between the time of the Apostles and 787 AD at the 7th Ecumenical Council held in Nicaea. I cannot answer the 2nd part of your question very well as I do not know what the Roman Catholics believe about their own Canon law. We Orthodox hold these Canons in extreme esteem. They help us guard our Faith and preserve our Holy Tradition. They help the modern man KNOW what the Tradition has been and is now (depending on the church and jurisdiction).
You asked: "...within the Orthodox Church organization, is there such thing as the Ultimate Authority, which oversees all ecclesiastic theological, moral and disciplinary matters? In the positive, what is the name?"
The Ultimate Authority IS Jesus Christ. But what you're asking about is administrative authority, a governing person or body that oversees these important matters. Like the Pope right? The problem with making one human the "ultimate authority" is that you place the foundation of your church on the shoulders of sinful men. What should happen if his shoulders are weak? What should happen if he is utterly terrible and betrays the faith in favor of pleasing other men? The church will crumble.
Our administrative authority comes from our synods, our collections of bishops who guide the churches (the Church) on the path to salvation. They do not do this of their own accord but, if they be truly Orthodox, by adhering and enforcing the Canons established by the Holy Fathers over 1,000 years ago. This is how it has always been. For a Scriptural reference to this, read Acts 15, wherein the administrative function of the synod, or council, is established.
You asked: "Can you say that any Orthodox Church that joins [or joined] the WCC can still be a true church?"
No. They break several Apostolic Canons in doing this:
"If any clergyman or layman shall enter into a synagogue of Jews or heretics to pray, let the former be deposed and let the latter be excommunicated." - Canon 64
Which leads to: "If any one shall pray, even in a private house, with an excommunicated person, let him also be excommunicated." - Canon 10
Those who call themselves Orthodox and pray with Protestants (heretics) have led themselves into excommunication from the Church.
You asked: How do I know I am receiving divine grace through the Sacraments if the church that I am in is without grace in the first place?
You're not receiving divine grace from the sacraments... Because those aren't sacraments. If the church you attend is without grace then it is not a part of God's Church; how then can the bread and wine be His Body and Blood? You are not receiving the Body and Blood of Our Lord Jesus Christ - you're only receiving bread and wine.
You asked: Anybody, who is in search for a true Orthodox Church anywhere in the world, where he/she should look and what is the right question to ask, in order to avoid making a false path?
Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you: For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened. (Matthew 7:7-8)
You ask God for the truth and His mercy. No matter what the cost. And you keep asking. Hoping. Praying. Have faith that He loves you and wants you to be with Him in eternal communion. And that He will lead you there...
However, I think you're looking for a different kind of answer. Ask if they are Orthodox, as in Eastern Orthodox. Ask if they follow the Old Calendar. Ask if they are in communion with anyone involved with Ecumenism (that includes any "orthodox" church in the WCC). Unfortunately, this part is tougher, but you need to find out about the church's/jurisdiction's history. For yourself, with internet, that will be simple. Not easy, but simple. These are trying times and it will get confusing and complicated - keep at it and you'll find it. And once you think you've found it, I personally think you should keep challenging it. Because we live in a very dark time; we are close to the end. And St. Paul prophesied that many would fall away from the true faith (2 Thes 2:3).
Nadir, this website was very helpful for me in learning about True Orthodoxy, the Calendar, Ecumenism, etc. It helped me in dealing with my Roman Catholic concerns. It's helped me in many ways: Orthodox Info
Please correct me, everyone, if I have posted any errors. Please pray for me that I may be forgiven for any indulgences I may have taken with these posts. Thank you.