gmx wrote: What parts of the Jesus story could have circulated independently,
I don't think we have anything independent due to the nature of the information being spread and shared at Passover. Plus there was never a center place of origin for any aspect of he movement less the very small amount of historical core related to Israel.
You also have the fact this movement was the divorce of cultural Judaism and the adoption of a perverted Hellenistic Judaism that was in fact, very diverse in its own nature.
and what was the common core of the story that captivated all these distributed centers of innovation off that core?
The perceived sacrifice of a crucified Galilean by Hellenistic Proselytes in the Diaspora who made a deity out of a man no cultural Jew would have ever done due to its blasphemous nature.
It seems a key question to me? What geographically-pinned chronology readily yields to that outline?
There is no one place we can pin anything to.
It Is my opinion, even if the man is not historical the standing temple and Passover traditions with half a million attendants yearly, of which many from the Diaspora found value in the one god concept and core values of Judaism but did not want to be or follow cultural Judaism. Euhemerism started and we see developing theology based on the text of Judaism that welded the martyred Galilean to the previous text. We see the Apotheosis competing with the Emperor who was the first "son of god"
Basically we see Hellenistic cultures in the Diaspora who wanted monotheism and were tired of worshipping the Emperor a corrupt politician as "son of god" and did not want to be identified with trouble making rebellious Israelite Jews, so you have Hellenism welded to Judaism