"All true believers who rely on Christ alone by faith alone are members of the one body of Christ, part of the ekklesia."
And one could ask, Did Abraham Isaac, and Jacob, ever say they "relied on Christ alone"?
So I could agree with you only if we agree that this "in Christ alone" may be implicit in people who actually do not confess Christ with their lips. Abraham, Isaac, and Jacob --- yes, even Adam and Eve --- hoped, but did not necessarily understand or know in Whom they hoped, Jesus Christ Our Lord.
So an implicit hope, even, is seen as apart of a saving faith.
Since St. James says we are NOT saved by "faith alone" and St. Paul says that if you had faith such as to move mountains, and had not love, you are nothing.
So this "faith" --- is it "faith alone"? If it is to be defined as a "living faith," which would include hope, and love, and good deeds, just as Paul and James define it, then --- OK, if it's "living faith," we're in agreement again.
"The ekklesia (those called out by God) have only one leader and that is Christ as their High Priest."
Well, yes. But even here, it's true only if you have a rather fuller understanding. In both the OT and the NT, God appointed priests, patriarchs and kings to lead and shepherd His people. Even though we have only one Leader, who is Jesus our High priest, He has never ceased to provide these earthly leaders, teaches and shepherds for us in every age:
Matthew 28:19
Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.
Matthew 28:20
teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.
Acts 13:1
Now there were in the church that was at Antioch certain prophets and teachers; as Barnabas, and Simeon that was called Niger, and Lucius of Cyrene, and Manaen, which had been brought up with Herod the tetrarch, and Saul.
1 Corinthians 12:28
And God hath appointed some in the church, first as apostles, secondarily as prophets, thirdly as teachers, after that miracles, then gifts of healings, helps, governments, diversities of tongues."
These are obviously not invisible teachers and invisible governments. These are visible ones, appointed by God in the Church. That entails a certain administration, a certain structure, an certain visible, institutional aspect of Church we can't really refuse to acknowledge. It's Biblical.
2 Timothy 1:11
"...whereunto I [Paul] am appointed a preacher, and an apostle, and a teacher of the Gentiles."
Titus 1:5
"For this cause left I thee in Crete, that thou shouldest set in order the things that are wanting, and ordain elders in every city, as I had appointed thee."
Something to think about.
However, I'd asked what "members of One Body" as in "Body of Christ" means to you. You answered mostly about the idea of "ekklesia," but did not relate quite how this is the Body of Christ, that is, with many different members cooperating together to perform different functions, that is, with an essential, close, living unity in which they depend upon one another. Much like eyes and ears hands and feet and so forth. I would like to hear more about that.
One could but if the answer to that is in question more space is needed then will be taken here or by this poster.
>>So this "faith" --- is it "faith alone"?<<
Yes, it is the faith alone that saves. The rest is the result, evidence, and consequence of that faith. Saving faith will naturally produce the proof and evidence of that faith.
>>He has never ceased to provide these earthly leaders, teaches and shepherds for us in every age:<<
Matthew 28:20 teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.
Not some stand in or so called vicar.
Acts 13:1 Now there were in the church ekklesia that was at Antioch
Not Rome or some other centralized rulership.
1 Corinthians 12:28 And God hath appointed some in the church ekklesia (at Corinth), first as apostles, secondarily as prophets, thirdly as teachers, after that miracles, then gifts of healings, helps, governments, diversities of tongues."
Not first a pope, then cardinals, then bishops, then priests. Next to last was administrators. Those who administer the affairs of the local group. Not once is a central organized dictatorship or controlling group set over all of the local assemblies.
>>However, I'd asked what "members of One Body" as in "Body of Christ" means to you.<<
Those called out by God, the ekklesia, are all part of the body of Christ. The local ekklesia consists of those that belong to the universal body of believers who because of geographical location meet as a group. In each of those groups will be those who have been called to different types of service to the group. Each local group will assist and support one another and as they are able will also give assistance to other groups of believers who may need assistance or aid.