Thanks, Altara. Will contact Brelaud and Briquel-Chatonnet. You should also take a look at the paper by Christelle and Florence Jullien (“Aux frontières de l’iranité: “nāṣrāyē” et “krīstyonē” des inscriptions du mobad Kirdīr. Enquête littéraire et historique,” Numen, vol. 49, no. 3, 2002, pp. 282–335). Just like Brelaud and Briquel-Chatonnet, they also make the case that Persians one some occasions referred to Christians as nāṣrāyē. In other words, they support your preferred explanation.
Rather, I support their explanation
Giving the sources, they seems to me convincing.
Maybe, but as you said to me, the issue is not that simple either. Gallez's hypothesis, granted, is the most extreme version of the Jewish-Christianity hypothesis. But I must take some issue - assuming I understood you correctly, since you were talking about Gallez - that the Nazoreans are not mentioned anywhere.
that they are never mentioned as Gallez describes them in some of their beliefs in his thesis, in any texts, even Epiphanius.
To be fair, and going back to what you said, this is not a simple matter, as this very same inscription has now been interpreted by four scholars (in addition to your source, see the reference I gave above) in a completely different way that does not support the Nazorean hypothesis.
Yes. Giving the sources, Brelaud at al. seems to me convincing.