Oh wow! I was startled today looking at my phone when I clicked on the link of this forum's updates. Thank you so much!
Elisabetha Winter is my great-great-grandmother.
I found their children's information on those books that Serbia made available recently online, but it is missing one child, Georg Henke, born 18.09.1870, †21.10.1921 (my great-grandfather). And I have their last son as Karoly (also by the same books on the Serbian website).
I always thought that Martin (or some of them) were born in Franzfeld, on that time that there are no books, and moved to Mramorak. A late distant cousin, granddaughter of one of my grandfather's brothers that stayed in Mramorak (and later moved back to Germany), and her father were subscribers of the Die Franzfelder.
Thank you! I'm trying to absorb all this information.