Johansen brothers: Hadsel to America after 1910

I'm looking for my great grandfather and his brothers: Johan Dahl Johansen born 1889 Hans Edvart Johansen born 1895 Hilmar Johansen born 1886 My grandmother was born in 1910 but sometime before or shortly afterwards, Papa Johan and his brothers went to North America. Apparently they are the 3 brothers found in the 1900 census for Hadsel. My grandmother is still alive. Various stories are around that one brother went to California, one to Washington state and maybe one even returned to Norway. (Also that one or more perished in WW1.) I'm about to start sending away for death certs for some of the potential suspects. Any other suggestions? Any help MUCH appreciated. thanks!!