I’m thinking that explaining why some things that Hebrews and the epistles say about Jesus don’t look like anything in the synoptics...
I really think you'll have trouble making that point.
I see another possibility, that sometime after the death of Jesus, possibly soon after, maybe as soon as they became aware of His exaltation, those things became obvious to some of the disciples.
I rather think that's the stated case, rather than 'another possibility'?
I think we can safely say that when Jesus was crucified, his followers thought that was it. The Resurrection took them all by surprise.
The Synoptics never present Jesus as a priest. This is a Hebrews development anchored in Jewish mystical traditions.
Melchizedek appears only in Hebrews, and there as a nuanced theological argument about the authority of the Rabbinical priesthood – one can hardly doubt the Synoptic authors would have been aware of him.
The Synoptics were presenting Jesus in his own words and his own deeds – which they saw spoke for themselves. That Jesus fulfilled the messianic prophecies made to Israel was the primary focus – mystical speculation is the stuff that goes on round the edges.
Jesus says "But I tell you that there is here a greater than the temple" in Matthew 12:6.
The Synoptics never call Jesus the “second Adam” or “heavenly man.”
I disagree.
The Synoptics present Jesus as a "heavenly man" – Jesus' Son of Man self-reference is to the figure in Daniel 7. The Baptism, the Transfiguration, the miracles, all point to it. His authority in his own right to forgive sin, and his self-declaration as Lord of the Sabbath all point to it.
Paul's presentation of the
soma psychikon and
soma pneumatikon is unique to him. The terms exist in Greek literature, and the general idea exists in Jewish speculation, but his contrasting the present earthly body with the future spiritual body is a distinct Pauline formulation.
That the body is animated by the soul is common in ancient thought, Paul's description of resurrection and transformation from a perishable body to an immortal body powered by the Holy Spirit is a unique theological contribution.
The Synoptics present Jesus as a teacher of wisdom, but not as Wisdom itself or as cosmic Logos.
Scholarship disagrees with you here.