Frels and Hopken Genealogy

I'm doing research for ancestors of my husbands family. Fredrick W. Frels b. 2 Feb 1840 came to America on April 5, 1885, from Oldenburg, Germany, to Filmore, County Nebraska. He came with his wife Catherine E. Hopken Frels b. 24 Mar 1839 and two children; Elizabeth b. 8 Apr. 1866 and Henry b. 2 Oct 1878. Their children were Elizabeth, Henry, George, Eda, Jennie, William and Gustav all born in Oldenburg.

Who were the parents of Fredrick W. Frels and Catherine E. Hopken. We'd like Fredrick and Catherine's marriage date and marriage place in Germany. Did Fredrick W. Frels have siblings?

If I have written this message to the wrong person; please forward it to the correct person.

                                                                                                  Thanks so much for your help. Gloria