I agree with your reading and solution of the
monogram - except 'diakonou' in stead of 'diokonou'. You would have to look up various prosopographic studies (like PMBZ -
http://pom.bbaw.de/pmbz/index.html - I checked and our Markos and
Kallinikos are not in there) to see if there's any additional information. But that does not happen often, especially if the individuals are of relatively modest rank.
(By the way: I split up the
thread because this is a different seal
type)
Regards
Gert