For over twenty years I have been researching Brunkens around the country. They mainly settled in TX, IA, IL, WI, and there are two groups in NE:
Lancaster and
Platte Counties.
Diederich
Brunken who homesteaded in
Platte Co. NE is my great-grandfather he died before 1920 Census.
The
Lancaster Brunkens are not related to the
Platte Co. Brunkens. They immigrated from different places in Germany.
If you let me know details about your Brunkens, or why your niece thinks
Platte Co. Brunkens are related I might be able to help connect you to the right family.
Marian