Marvelous!Al-Shahrastani, in his "Book of Sects and Creeds", wrote about Jews that accepted Christ as the Messiah living around Mecca and the Hejaz area in general, so it's not much of a stretch to consider these to be remnants of the historical Ebionites that lived in that area prior to Islam.
About 50 years earlier the Iberian rabbi Benjamin of Tudela also encountered Ebionites in north-western Arabia.
I was googling, and found articles relating to Jewish Christians in history on Brill, but my university only has access to the Islamic content for some reason. Drats.
The Islamic content does include an article on the Ṣābiʾa, who might be related to the post-Temple Elcesaites and Ebionites. I might simply call the heresy "Judaeo-Christian" to encompass all these groups.