I don't see any passenger lists for this family in the 1890's, but a WWI Draft Registration Card has Wilfred Reginald Hill born 22 Nov. 1895 in St. Louis, Missouri and living in Portland, Oregon. He was listed as born Nov. 1894 on the 1900 Census, though.
According to the 1910 Census, George filed his first papers to become naturalized, so those records could potentially have a ship's name and date on them. The issue is finding them.
It appears that George sailed from Sydney to Victoria, BC, Canada in 1916 and was still an alien. It was written in on the manifest that he was in the US from 1896-1915. George also sailed from Auckland, NZ to Seattle, Washington on the SS Niagara in 1920. There are manifest markings indicating that he did subsequently pursue naturalization. It is written in "Nats. 6-28-34 #21-6565". According to this -
http://www.jewishgen.org/infofiles/Manifests/natlty/ - the date may be his naturalization date or when his trip was verified.