Second, what do you call Christian Jews, or did you miss the point that Christ and all of his Apostales were Jews?
I won't speak to Jesus, as I will annoy Christians.
As far as his Apostles and other early Christians, they belonged to a diverging Sect, which became another religion over a period of 200 years.
As are a lot of my father's relatives, Orthodox Christian Jews....which means they are Jews by race not religion.
They were Jews by birth, but are no longer Jews. You can no more be a Christian and Jew than a Christian and Muslim.
Or what about Gentiles who convert to Judism? Are they now ethnically Jewish?
Gentiles who convert are Jews by religion, not ethnicity. However, they are accepted as Israelites without a tribe.
Believe it or not, even the Hebrews were once pagan.
I am aware of this. However it is religion that became the defining character.