My queries to professional Armeniologists have gone unanswered, doubtless because they are very busy. But I am still interested to learn whether there are catenas on the gospels in Armenian.
A thought struck me last night. Suppose that none have been published? Where could we find catenas?
The answer, surely, is to start looking at catalogues of Armenian manuscripts. These will surely indicate the general content of manuscripts. If there are catenas, they will probably indicate the authors quoted.
The French National Library has PDF’s of most of its catalogues online (bless them!). This includes a splendid catalogue of their 300-odd mss, with a nice history of the collection at the front and some good indexes.
The results were a little disappointing, tho. So in the Index of subjects on p.1002 (p.538 of the PDF), there are lists of mss by subject. But catena is not one of those subjects.
However there is an anonymous Commentary on the genealogy of Matthew and Luke in Ms. 303, items 4-5. This is something Eusebius talks a lot about in the Quaestiones ad Stephanum. Probably the material here is at least influenced by him. Unfortunately you would need Armenian to learn much more.
A few pages on, there is a category of Questions and Responses. Athanasius, Cyril of Alexandria, and John Damascene all feature. So, interestingly, does Philo! There is no Eusebius listed, but who knows what someone sat in the reading room ordering up mss might find?
Looking in the author index there are fragments of the Church History and the Chronicon in various mss. This is natural, since both exist in full in Armenian. But no other works are listed.
All in all, this was an interesting exercise. I learned more about the collection than I might have done. But so far, no material for the Eusebius Quaestiones.