Thank you for the Courtauld Institute's Lynch's photographs link. I had known of it, but the resolution of the photos has got higher since I last looked at it.
That photo of the Surp Karapet belltower (which is not in Lynch's book) is very revealing for the stone relief carvings on its facade. Left to right, first is a winged lion, then a winged human carrying a book with a cross on it, then an eagle, and finally a winged calf - these must be depicting the four evangelists. Below, framing the niches, are capitals in the form of twin dragon heads. A similar capital motif can still be found inside one of the surviving chambers of the monastery. In the five light coloured plaques at the top, the centre one looks like a bishop, or perhaps John the Baptist. The flanking plaques show angels with trumpets. The one of the far left seems to depict a baptism, or perhaps Adam and Eve.