Good points. Of interest in this vein is that Israel had long since been set aside in order for the Gospel of grace to become the active gospel for Gentiles and Jews alike, because under the Gospel of grace, the distinctions fall away in Christ. We are all saved by the same Gospel after the Kingdom Gospel had been laid aside until the end of the times of the Gentiles.
There is some resistance out there claiming that the same Gospel was active in the Gospels as what was active throughout the epistles. I simply must question, then, the motives behind such a claim, because there were two Gospels at play at the same time through a short transitional period that we can see here:
Galatians 2:6-9
6 But of these who seemed to be somewhat, (whatsoever they were, it maketh no matter to me: God accepteth no man's person

for they who seemed [to be somewhat] in conference added nothing to me:
7 But contrariwise, when they saw that
the gospel of the uncircumcision was committed unto me, as
[the gospel] of the circumcision [was] unto Peter;
8 (For he that wrought effectually in Peter to the apostleship of the circumcision, the same was mighty in me toward the Gentiles

9 And when James, Cephas, and John, who seemed to be pillars, perceived the grace that was given unto me, they gave to me and Barnabas the right hands of fellowship; that
we [should go] unto the heathen, and they unto the circumcision.
We see here that two distinct Gospels were in play at that time as an overlap until the Gospel of grace became the one and only active Gospel until the end of the times of the Gentiles, so the distinction is evident.
Some have said to me that this only addresses to what groupings the various of the apostles were assigned to preach the one and same Gospel, but that simply cannot be the case given the content of each one, with one requiring such things as repentance, baptism and enduring unto the very end so that they "SHALL" be saved, and therefore not sealed by Holy Spirit as is the case under the Gospel of grace.
I too at one time liked to believe that everything in the way the Lord does things all fit in the nice, neat little, warm, fuzee box of my preconceived ideas about how the Lord operates in this world and in the heavenlies. What a shock it was to me to see that I was trying to define the Lord and His modus operandi rather than the other way around.
MM