RE: Maria Glaub Mueller I believe Nicolaus Glaub was a German living in Hungary. There were Glaubs, Catholic and Jewish, in Hungary since they moved there from Bavaria in the 1700s along with thousands of other Bavarians. I met someone who descends from the Hungarian branch. Email me and I'll explain more about his branch.
First Papers My "Joseph Glaub"'s mother's name was Maria according to his 1898 death doc, so there could be a connection. He was born just a few years earlier than your Maria, so they might be cousins. I couldn't find Joseph's "first papers." Perhaps he never had any. Hopefully your Maria has them at UWM.
RE: Maria Glaub Mueller If you go to the UWM Library, there's a room with the "First Papers" of immigrants on I believe the 2nd floor next to the stairs. Nicolaus Glaub might be a German Catholic from Hungary who moved to the U.S. in the 1870s or 1880s. Or perhpas just his daughter and a son moved to the U.S. from Hungary or Germany (Bavaria or Rhineland).
Look for her "First Papers." If she's from Hungary or "Austria", which probably controlled Hungary at the time, let me know.