This was not a restored Israel, as envisaged by OT prophecy, for instance (or any OT expectation for Israel’s future).
So what does Paul mean when he says that the Gentiles have become part of a structure that is built on the foundation of the prophets? Either this was a restored Israel as envisaged by OT prophecy (ie. Israel at the centre of a transformed empire) or it is meaningless.
(Actually, I’m inclined to think that the reference is to New Testament prophets.)
The promises to Abraham, to which the gentiles are now heirs, went beyond the borders of Israel, and beyond anything envisaged by OT prophecy.
The promise to Abraham was only that those nations which blessed Abraham’s descendants would be blessed (Gen. 12:3). This assumes the independent existence of Israel apart from the nations. There is no Old Testament vision of a supra-Jewish or post-Jewish people of God, nothing that goes beyond the borders of Israel. The vision is always of an intact Israel in the midst of separate nations, and when God acts to save his people, etc., the nations respond with worship and tribute.
I’ve been skimming through Markus Barth’s excellent analysis of the text. He says:
Through his incorporation into Israel a Gentile finds communion with God. God himself, and not an indigenous quality or superiority, is the mystery of Israel. That man is under God’s protection who submits to Israel’s king and becomes a citizen of Israel. He is not only a citizen of an earthly city or state but a “member of God’s household.” (M. Barth, Ephesians 1–3, (1974), 270.
Needs more careful reading, though.
Of course it had to be abolished so that gentiles could be fully included - not in a new Israel (which is mentioned nowhere, not even in the texts you have quoted), but in “the new man” of Ephesians 2.
But when you put it like this, the abolition of the Law lets Jews out rather than Gentiles in. If the new man is not Israel, there is no need to abolish the Law in order for Gentiles to become part of this new third people.