Hi Patricia, I looked at your tree and it's looks good.
I would like of offer a few corrections if I may.
In 1881, when Anton came over, he arrived in New York port, not Ellis Island. Ellis Island started in 1892.
Anton's origin I believe is Krenovice aka Chrenovice, near Ledec Nad Sazavou, Caslav. This info came from the NE-KS Czech Settlers book by Sobotka. This town does not yet have their birth, marriage, death records digitized on line yet.
As for the mystery of the "Grandma", I believe she would be
Josephine/Josefa Pribyl born about 1815, probably in Krenovice.
Josephine traveled with Anton and Mary on board the Hohenstaufen and is found to be living with them on the 1885 Nebr. State census in Victor, Nuckolls,NE. She is listed as Grandma on this census, so she's not Mary's mother.???