As for Abel having received the Gospel of Jesus Christ before Abraham, I do not believe this possible, because Abel's parents both knew God in person, they sinned (disobeyed God), and the curse was on al mankind until Christ with many who knew of God's mercy and grace throughtout the interim.
Gal 3:8 And the scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand unto Abraham, saying, In thee shall all the nations be blessed.
The holy men knew of grace and they knew of God's mercy being fresh every morning, as it is written, but of a Savior for all mankind, I believe not, though they too awaited His coming and His revelation of salvation.
Lam 3:22 Because of the LORD's gracious love we are not consumed, since his compassions never end.
Lam 3:23 They are new every morning—great is your faithfulness!
It is probable Abel knew God is good always, and thus he made offerings to God which He accepted, but had He known the Gospel of our Lord, Yeshua, He would have also known there is no other sacrifice for sin than the Lamb of God, and there is
Separate kind of references. One to seeds, many and the other as the things of God,seed, as to one.
Never do the two kinds (fleshly and spiritual ) become one. The corruptible as that of Abraham does not inherit the incorruptible seed (Christ)
I think the gospel was first given to Abel . He had the faith of Christ needed to believe God. His blood still cries out.
We should be careful how we use the word Abraham that we do not have the faith that comes from hearing God in respect to a sinner and not the faith of God by which we can believe God. . The Catholics use the name Peter in the same way the non believing Jew used Abraham as if he was our father in heaven . The faith of Christ is that which mutual works in all believers. if we have our new faith in respect to Abraham we have already blasphemed the holy name by which we are called
The man Abraham has no part of our salvation.