Very interesting photo, it appears that both are Feldwebel, or Sargeant-Major, I would assume that they come from Klatovy, which is just north of OberÖsterreich, that would put them in a german regt (as opposed to a Hungarian regt) They would have been Czech, and this photo could have been taken as late as the second year of the war, although I suspect it is pre war. As far as determining which regt they are, is uncertin, but I would venture to guess that they are of the 2nd Graf Parr of Prag, as the facings appear to be very dark and the buttons look to be white (silver) rather than yellow (brass or gold). and the facings for this unit is black, but now we run into the trouble of determining colour from a photo. the age of the photo could be such that Yellow (the facing colour of 7th Herzog von Lothringen) could appear as nearly black. The other choices for someone from this region would be the 10th and the 14th, but both these regts had yellow buttons.
Best wihses
Gus