Surname Saturday - HANSEN

My Norwegian grandfather, Adolph. left Norway in 1894 with his sister Dagny and brother Artur. They left behind 2 brothers, Sigurd and Thorolf, along with their father and step-mother. Adolph, Artur and Dagny traveled to Chicago where their deceased mother's sisters and brother were living. At 14 years of age Adolph finished his education. In the 1900 census he was working as a packer and he and Artur were living with their aunt and uncle, Olga and Axle Pedersen. Adolph married Henrietta Burbach and they had 2 children, Dorothy and Donald. Donald was my father.
About 10 years ago, I decided to find out more about Adolph's family. It was challenging since my Hansens didn't consistently use the typical naming patterns. Also, when Adolph left Norway he traveled under his middle name of Halfdam. I finally found their emigration records from Norway by looking for his sister Dagny. Looking for help on the ancestry.com message boards, I made contact with a Norwegian author who was writing the biography of Adolph's father, Adolf Hansen. Adolf Hansen, born 1852, was a noted musical composer and the biography was in honor of his 150th birthday. The author and I wrote back and forth often and I was able to order a copy of the book and also received a recording of the concert of Adolf's music played for the birthday celebration.
Adolf, the composer, had 2 wives and 10 children most of whom I've been able to find. The Norwegian naming patterns appear to have been followed sporadically at best. Adolf was born Johannes Adolf Waldemar Hansen but later used Adolf Hansen. Looking for his father, I expected to find Hans? What I found was that his father's name was actually Martin Hansen. When I looked for my grandfather's christening records, I found him listed as Adolph Johannsen! A rose by any other name?