Thanks for the questions.
1. What is "a few thousand"?
Honestly, our jurisdiction is fairly small to begin with. We don't have any official numbers, but the Autonomous Metropolia of Western Europe and the Americas (now two Metropolias) before the confusion as a whole probably only has about 10-15 thousand people.
2. On what basis do you say there are 70-100 million Orthodox instead of, say, 150-300 million?
The official Orthodox hierarchies have worked with inflated numbers for a very long time. Let's take Russia as an example. Indeed, one estimate says there are 150 million Orthodox in Russia; unfortunately this would mean that there are more Orthodox than people in Russia (Russia's population is 138 million according to the CIA world factbook.) https://www.cia.gov/library/publications/the-world-factbook/geos/rs.html#People
If we look at the numbers and apply a 15% Orthodox population (which is still not a conservative estimate) that's only about 20 million people.
The numbers don't add up. Applying this across the board (as Russia is usually considered to be 1/3-1/4 of the population of Orthodoxy worldwide) we can see that the "300 million" is grossly inflated.
3. Who *are* these "sister churches"? Can you be more specific, please?
Our Sister Churches are listed here. This still includes Milan before the schism. The English in it is very poor however; it translates "Bishops" as "Archpriests" in English.http://metropolsynodgoc.blogspot.com/p/ecclcommunion.html
4. Re: WR Antiochians and ROCOR...Is not their confession of faith the Nicene Creed? If not, what is it, and precisely how is it different from *your* confession of faith? This is from the website of St. John the Baptist WR Antiochian Church in Maryland:
Nice touch with the Latin; the Nicene Creed in Latin is fine too if you strike the word "filioque" from it.
The creed is the same for all of us. This is correct. However, we should not take a minimalist approach. The creed is an exposition of the main dogmas of our faith, but it can be held to by heretics. When we believe in "One, Holy, Apostolic Church", we believe in the Councils of that Church, and the teachings expounded therein. The creed, for example, says nothing about the Holy Icons. That doesn't mean that we can "skip them".
5. Are you saying that our (ROCOR, Antiochian, OCA, GOA, etc.) bishops do *not* "adhere obediently to the principles of the Faith once delivered to the Saints and do not use their power to excuse themselves from doing so."? If so, how are they not?
That's a very good question. Unfortunately, there just isn't enough space to write about the abandonment of the faith on the part of the official hierarchy. I would suggest a few good books:
1) The Orthodox Church and the Ecumenical Movement, Fr George Macris
2) New Zion in Babylon, Vladimir Moss
3) The Struggle Against Ecumenism, HOCNA
4) Russia's Catacomb Saints, I.M. Andreyev
5) Is the Grace of God Present in the Soviet Church? same author
That's a start.
Now, the ROCOR is unique in that she "stood apart" from so much of these disasters-- until the period of union began to "shake out" those who were faithful to Her original teaching. Sadly, that led to splintering among the traditionalists until the 2007 union with the MP.
Now the Orthodox traditionalists are just trying to pick up the pieces.
6. What are the "heterodox" principles or beliefs you keep referring to? Can you specify, please?
Can you point to a specific context? I'd be glad to answer, but as you can see, a lot's been tossed around....
7. Please define "apostolic succession", especially with regards to those bishops you have referred to as athiests.
The Orthodox teaching of Apostolic Succession is the teaching that the Bishops hold the line of succession to the Apostles in terms of the Grace of the Church being passed down from the Apostles to the Bishops of the present day. A good definition is right on OrthodoxWiki: http://orthodoxwiki.org/Apostolic_succession
What I was referring to, specifically, is that heterodox, nor atheists, cannot be granted the grace of the Apostles, because they are not Orthodox (Apostolic Succession, unlike the Roman teaching, is not mechanical: it does not confer the grace onto someone incapable of receiving it.) During the Soviet period, the "Bishops" ordained at the behest of the Soviet government were sometimes not Orthodox, and in some cases did not believe in God.
I usually use the example of vesting Jehovah's Witnesses. You can vest one, "ordain" him, and he can "ordain" whomever he wishes, but the grace of the Church is not being passed down. This is, effectively, what happened with the MP; apostates continued ordaining apostates, and after the fall of the Soviet Union, sometimes good and well-meaning people with nominal Orthodox faith were made "Bishops". But because their ordainers were themselves defective, they can't hold the grace of the episcopate.
I hope that helps.