The OT saints, as well as the disciples (except for one of them) all believed in Christ.
Job 19:25: I know that my Redeemer lives,
and that in the end he will stand upon the earth.
John 8:56: “Your father Abraham rejoiced at the thought of seeing my day; he saw it and was glad.”
Numbers 24:17: “I see him, but not now;
I behold him, but not near.”
For belief in Christ was and is the only way to salvation:
John 6:54: Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day.
There is only ONE PEOPLE of God, not two. One olive tree (Rom 11), not two. There is and always has been only one plan of salvation.
Galatians 3:16: The promises were spoken to Abraham and to his seed. The Scripture does not say “and to seeds,” meaning many people, but “and to your seed,” meaning one person, who is Christ.
Galatians 3:29: If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise.
Galatians 3:28: There is neither Jew nor Greek, slave nor free, male nor female, for you are all one in Christ Jesus.
BTW, did you know that Abraham means “father of ALL nations”?
I could send you more verses (there are many more), but suffice to say you can believe whatever you want, but you can’t argue against God’s Word and expect to win.
Why did Christ rebuke those disciples he met on Emmaus road (Lk.24:25-26) for not believing in what had to happen as prophesied?
The verses that you have stated have nothing to do with what the Apostles and disciples believed.
None of them believed that Christ was going to the Cross to die for the sins of the world and be raised again
That was something that they had to learn after the fact, especially Thomas!