I need to correct my earlier post, having learned a bit more.The father of the G. Hermann Wille to whom I refer (and about whom Mr. Shaw inquired) was not, as I had speculated, Charles/Carl/Karl but instead Christopher/Christoph/Christof WILLE, a professor, presumably in or near Hanover. His mother was Louise/Louisa MEIER (died c. 1895).
No knowledge here of Hermann's siblings, if any. (May have emigrated with a Karges or Karger and a Klastermeyer/Klostermeyer--but apparently not accompanied by other family members.)
No knowledge of Christopher's siblings, if any.
Siblings of Hermann WILLE's mother, Luisa MEIER (c.1805-1895), included Hermann MEIER (possibly U.S. immigrant bef. 1860?); Karl MEIER (married Johanna Hille(?) of Hohen 13 Dec. 1860); Julius (m. Aguste Unknown) MEIER (possibly raising a child Edward AUGER); and possibly Auger MEIER, who had a daughter Hermine.
If anyone has any leads based on these names, please pass them along.I'd certainly be glad to share what little I have, including photos of Christof and Louise Meier Wille taken c. 1860.