Well, if you’re confident that Mina Stiasny was your GGM, then for help building your genealogy, you should consider looking for Samuel Stiasny’s family. A quick search shows that the two boys, Julius and Sidney, both married and had children. Julius’ headstone is even on the internet! You can try to find those families and that should help you tremendously. You now also have the parents of Mina Stiasny from the sons’ NYC marriage records. Let us know what you find!