Yeah, but if Jesus is both God and man, and the Holy Spirit is in the Bible, it‘s still pretty easy to come to the doctrine of the Trinity as a conclusion.
But does Jesus say that he is God? I don't think that the CNT OTL makes that claim explicit. It was something elucidated by the Church Fathers based on what Paul wrote, and was contested in the early Church by e.g. Arianism.
AFAIK OTL Trinitarianism ("high Christology") developed over time as Greek Christians grappled with the low Christology of "Jesus is important and divine but we aren't sure exactly how," and it was a way for polytheistic converts to a monotheistic religion to square the circle of certain Hellenistic theological assumptions about God(s) incarnating into mortal bodies. Same with the adoption of iconography in worship, which built on the Hellenistic tradition of idols and understood to be permitted in specific limited ways ("Jesus was God manifest in the shape of a man, so bowing towards images of that man cannot be idolatry" etc.) and so on.
Are the Apostolic Church Fathers Trinitarian? I thought they were Adoptionist, which is a non-Trinitarian theology?
The Apostolic Church also went through a lot of the same Christological debates as OTL, so there are several miaphysite/Nestorian/other communities scattered about. There’s also probably some sect that tried to further syncretize Christianity with Zoroastrianism(i.e. Jesus as an Amesha Spenta, yasna as part of their church services). The Ebionites will call themselves Ebionites, but I might reuse the name “Restored Nazarene Church” for some other group later on.
... huh. Okay. Your story, you write it in the way that makes the most sense to you.
The Ebionites do follow Kosher dietary laws(with maybe a few differences, since they use a different Talmud).
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The Ebionite Talmud will most likely be compiled under Abu Yusuf, but being built on earlier tradition dating back to the first introduction of Ebionites Christianity to Arabia. Although they are not trinitarian, Jews will still not accept their rulings as legitimate because they see themselves as Christians first and foremost.
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The Ebionites have a different canon, and so do not recognize the Acts of the Apostles anyanyway.
Jews will definitely take note of the praxis and doxa of the Ebionites and make their own decisions about what the Ebionites are, within a Jewish halachic framework, despite their self-identification as one thing or another; look at OTL rejection of "Messianic Jews" based on their essentially-Protestant Christian theology.
Remember that Trinitarianism is seen as straight up polytheism, three gods in a trenchcoat, by OTL Jewish halacha. So if the Ebionites are monotheistic and not Trinitarian, then they will probably not be perceived as Christians by Jews ITTL. Instead, they will be seen more like Muslims are OTL (i.e., "Noahide-approved & fully legitimate for non-Jews" by the ecumenical and lenient, "at least they're not idolaters" by the parochial and stringent).
Or - and this is the truly radical improbability, and contingent on the Ebionite Talmud being very similar to normative Jewish halacha despite their modified CNT - like Chabad Messianics are OTL (i.e. somewhere on a continuum between "sketchy and weird, but still a Jewish enough heresy" to "the religion most similar to Judaism").
ITTL Judaism's acceptance of their halachic rulings will depend on where on that spectrum from "a Jewish heresy" to "polytheism pretending to be monotheism".