Is there anything approaching a historical consensus on this aspect of the conflict?
It was not.
I am busy now to elaborate, but here is a quick example where the International Criminal Tribunal for Former YU in the Hague ruled the war to be an international conflict.
Relevant part:
Nature of the Conflict
Trial Chamber II confirmed the existence of an international armed conflict between the Republic of Bosnia and Herzegovina and the Republic of Croatia at the time the alleged crimes were committed. Support for such a finding is based (i) on the direct involvement of Croatia and (ii) an agency relationship between the Bosnian Croats and the Croatian Government. The Trial Chamber's finding in this regard gives it jurisdiction over some of the crimes with which Rajic is charged, namely, grave breaches of the Geneva Conventions, under Article 2 of the Tribunal's Statute. Such crimes can only be committed during international armed conflicts.