DisillusionedJW....You made many good points. I agree the antisemitism of much of the Gospels is a secondary layer of the faith. Interestingly even in the most proJewish revision of Mark (called Matthew) the Jews are depicted as perpetually bloodguilty for the death of Jesus.
"His blood be on us and on our children!" Matthew 27:25
A key to unraveling all the tangles is to realize that as soon as a person says, The Jews did this or that or believed this or that" they are guilty of stereotyping and grossly oversimplifying the religious environment of the times. Half of the deaths of Jewish people were by Jewish people. On a small scale, like the death of the Teacher of Righteousness of Qumran to the civil war level revolts between the sects supporting or rejecting the Hasmoneans or the Maccabees. Josephus has just shown us the violent power struggles for the High Priesthood. IOW they were quite capable of violence over religious and political matters.
I'll share my present understanding of the early stages of Christianity. I cannot prove much of it, but feel it is consistent with the facts and works as a model.
I suspect the movement began with a soft-start. No single event or person initiated the religion. Rather it grew from the Hellenized Jewish conceptions of a Son of Man/ Son of God heavenly figure such as we see expressed fully in Philo and intertestamental literature. This topic has been discussed on this forum in a number of threads. It was a small step to envisioning an incarnation of this heavenly figure. This figure, previously known as the Logos, or Son of God was given a human story. A story almost entirely drawn from the OT and intertestamental imagery. This was not 'fraud' but pious inspiration (small i). This was the norm. Typological (dual meaning) reinterpretation of past writings was the lifeblood of Jewish religious culture.
The Jerusalem temple-focused sect was not a fertile soil for new religious ideas, it had devolved into a political institution that was deemed largely irrelevant by the much larger diaspora. It was here in the larger Jewish community that creativity vitalized the faith, it was here in the melting pot of ideas unchained by temple politics, that the roots of Christianity spawned. I'd place this soft start around 100-50BCE.
As I just said, the incarnation of the more approachable Son of Man figure required a narrative. This was drawn piece by piece through brilliant usage of scores of stories of Moses, David, Elijah, Judah etc. This apparently existed in oral forms for a short time (time of Paul) but then eventually written down. This was done by someone outside Idumea and a second or third generation Christian. (many scholars call it UrMark, an early form of Mark) The name Joshuah (Jesus) and the place became fixed by this same method of OT typology. It's also possible the myths of Messiah ben Joseph contributed to the fleshing out the story. Messiah ben Joseph - Wikipedia
The writer made clear he was drawing from the OT but later generations understood the narrative as historical and the parallels as prophesy literally fulfilled.
It also seems quite plausible that early on, the new faith attracted followers of John the Baptist. Some even assuming the new character was John reborn. (Matt 16:14) The miraculous birth narratives, also drawn from OT, were apparently previously attached to the JTB. It was this key element that anchors the story in time IMO. From there the story writes itself. The OT typological necessity for Jesus to die (on a tree) by forces of evil was quite naturally depicted as killed by Roman crucifixion.
This narrative (possibly written as a didactic (teaching) play) was popular and distributed among the communities of Christians (who from the start had diverse views). The literate leaders of these communities revised this narrative as each perceived the Jesus figure slightly differently. Many other narratives (gospels) and sayings were written at this time as well.
40-70 years later 4 of these narratives (3 synoptics and one with more Gnostic tone) were collected and elevated, becoming sanctioned by the congealing orthodoxy amongst the most politically savvy group. Names of persons in the stories are attached to them as authors.
As the centuries pass this orthodoxy is challenged by many rivals but the 4 narratives are further harmonized somewhat and weaponized into dogma and as a base of power. The same is done to a collection of Paul's writings. The book of Acts is written and a number of Pseudo-Paulines that cement the orthodoxy's (Catholic) positions. Revelation by John the Presbyter is eventually attributed to the same guy as the Gospel and a number of epistles. It is reluctantly adopted into the collection.
Take that for what it's worth.