I think that the dilemma (how could Marcion himself write a Gospel and be totally unaware of a historical Jesus in the presumed epistles authored by him) can be resolved only:
1) by assuming, with Robert Price, that Marcion authored the epistles but he was unaware of any Gospel.
2) by assuming, with Couchoud and Vinzent, that Marcion wrote a Gospel but not the epistles (that therefore are written by the historical Paul).
Tertium non datur. To think otherwise means to be not perfectly aware of what means 'absence of a HJ in Paul''.
My contention with this would be that the [Marcionite] epistles show a lack of awareness of a historical Jesus, or at least a disinterest. Rather, they focus on the importance of the one writing them, whether he be called Paul or Marcion.
I opt for the point 2.
May I ask why? For the most part I don't see a reason to not accept that Marcion authored the epistles, especially since I see them reflecting policies sanctioned during the reign of Hadrian, and 2 Thessalonians seems to make a passing remark at Simon bar Kochba.
Rather, I think it's possible that some letters were written prior to the composition of a Gospel by Marcion, and some written after. But that's just a theory of mine.
The issue as I see it is, what was
Marcion's Gospel? Was it a truncated Lukan text, or similar to it? Was it Mark? Or did it contain elements of all of the canonicals? I think Turmel was right in thinking that it was closer related to John. Coupling it and the Pauline epistles, then, demands that they be taken as a single compilation; or that they complement each other.
While I agree with Vinzent on the general thesis, I wonder why Couchoud and Ory -- 100% precursors of Vinzent in assuming Marcionite priority - didn't need to assume that Marcion was ''Jew''. But I suspect the answer: Vinzent has to satisfy the consensus's principle called ''Reductio ad Judaeum'' (any actor on stage has to be a ''Jew'' otherwise he is not an actor).
The problem here is thinking of Marcion as being apart from Judaism. But even his theology, or at least his writings, is dependent upon Judaism. It my have had trappings of Hellenism, but so did many schools of Jewish thinking at the time. It was predominantly a Jewish focused religious reformation.
The Gospel of the Hebrews shows (for that bit in our knowledge) the negative portrait of the disciples: this is clearly an influence from a previous Gentile Gospel.
I don't follow this, either in it proceeding a Gentile Gospel, that there was a Gentile Gospel, or the negative portrait of the disciples. It emphasizes the importance of James above the disciples, just as GThomas and Ascents of James. It is not as vehemently against the disciples as Mark is.
I think that it is inconsistent to accept the Detering's arguments to deny the authenticity of Galatians (particularly these arguments that claims the non-jewishness of the author of the epistles) and in the same time to claim the being Jew of the post-70 author of the epistles.
Not at all, if it's understood that Marcion was complying with the post-Kitos milieu of Hadrian's policies, while simultaneously acknowledging his dependence on Judaism, (as per BeDuhn's translation) then such issues are resolved.