"The other sheep are the Gentiles, a few years later (Eph Ch 3)"
It's Eph Ch 2 and I agree. Romans Ch 11 is talking about the Jews that don't accept Christ and how they are broken off and "a wild olive shoot" is grafted on in their place.
In John 10:16 Christ is talking to unbelieving Jews. The Jews, as a nation, were always God's sheep. His chosen people. But the individual Jews Jesus was talking to were not sheep at all as they were unbelievers.
Clearly the other sheep Jesus was talking about were the Gentiles. The interesting thing about this verse; He called them sheep. Jesus didn't say I have, or there are other goats that I will make into sheep.
This had to be years before Paul started his work, years before the Good News was given to the Gentiles. But they were already Christ's sheep.
Where am I going with this? Romans 8:28 through 9:26 "........And those whom he predestined, he also called; and those whom he called, he also justified; and those whom he justified he also glorified....."
One really needs to read and study the whole section. The point is, of course Jesus knew those of the Gentiles that were His sheep. He knows all His sheep.
Ephesians 1:4-6
"just as he chose us in the Messiah before the creation of the universe to be holy and blameless in his presence. In love he predestined us for adoption to himself through Jesus the Messiah, according to the pleasure of his will, so that we would praise his glorious grace that he gave us in the Beloved One."
BTW the "remnant" that will be saved are the scant few Jews that will be saved in spite of the fact that Israel, as a nation, rejected Christ.
Paul quotes Isaiah in the next verse (Romans 9:27) "THOUGH THE NUMBER OF THE SONS OF ISRAEL BE LIKE THE SAND OF THE SEA, IT IS THE REMNANT THAT WILL BE SAVED; "
Peace