HALVERSON/JOHNSON Stavanger/Bergen

Looking for information on EITHER of my grandparents! Grandfather's name was HALVER HALVERSON born: abt. 1878 in Bergen Norway? Came to America possibly as a child with parents around 1880/1881? Parents were: Halver Halverson & Abigail? They settled in Iowa, and Halver married a BELLE JOHNSON...born: 1877 in Stavanger, Norway. Belle had possibly been married before, as it seems she came over to America as a pregnant widow, possibly in 1902/1903?. She traveled with her brother Ole Johnson. I do not know Belle's parents names. One of these families maybe came in through Nova Scotia, but have no other information. If someone can point to the correct ship? Port of entry, port of departure, or if there is a long lost cousin from Norway out there...I'm happy to hear from you! Thanks, Stacey