I got a reply from the Univ of Vienna. It seems that Melety never taught there, but there were 4 Dutkevich professors that they had in their records. Maybe it will help someone else.

unfortunately, we have to inform You that we could not find a trace of Melety (Meletius) Dutkevich in our archive materials. But we found some other persons bearing the name Dutkevich in the “Matrikel”:
Bogdan 1901/02: phil. Fac.;
Johann: Johann 1856/57: phil. Fac.;
Stanislaus: 1884: theol. Fac.;
Michael: phil. Fac.

Yours very truly
Johannes Seidl