I did not invent the term ['Replacement theology]. It is commonly used in eschatology.
Indeed, it is commonly used by Dispensationalists, although it is a misnomer and a misrepresentation.
The dispensation of the Church Age began at Pentecost in Acts 2.
I refer you to Acts 7:38. I am not aware of a 'Church Age.' It seems to me to be an artificial construction.
There were no local churches before that, and there will be none in the millennium. Those are different stewardships from God.
The Church is the Bride of Christ and at the end of time He will present her
'To Himself a glorious Church, not having spot or wrinkle or any such thing, but that she should be holy and without blemish' (Ephesians 5:27). The Church is the Bride and she becomes the Lamb's Wife (Revelation 21:9; c.f. 19:7-8).
The passage you quoted is clearly specific to the Church Age, since it speaks of the "body of Christ." In Paul's letters to the churches he refers often to this metaphor, but it is never used for the Jewish people per se, only for the church, which merges Jews and Gentiles into one body. This is clear from Col. 1:24, which says, "Who now rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church."
This is the whole point; the Jews and Gentiles are now one, joined together in the Church of Christ. Do Jewish Christians not join churches? Of course they do!
See also Rom. 8:10 &12:5, 3 verses in 1 Cor., your verses in Eph. (specifically to a church), two other verses in Eph., & Col. 2:17. These passages are ecclesiological, not eschatalogical.
They are not ecclesiological, they are soteriological. Romans 8:9-11.
'Now if anyone [Jew or Gentile]
does not have the Spirit of Christ, he is not His. And if Christ is in you, the body is dead because of sin, but the Spirit is life because of righteousness.....etc.' This is about salvation, not about the Church.
In short, there is only one people of God. This was God's intention right from the start (Genesis 12:3b etc., etc.). God built His people first from one man, then from one nation, but His purpose was always one elect people from
'all nations and tribes and peoples and tongues' (Revelation 7:9). This does not by any means rule out a great future revival among the Jews, but nor does it rule out the same among the Arabs.