Ellis Island was for immigrants sailing on civilian ships from other countries for entry into the United States. They were given medical check ups, checked for contraband and various other checks and the filling out of paperwork before they were allowed past Ellis Island.
War Brides of American Servicmen and their American Citzen children were not "Immigrants". The brides/mothers were vetted in the country they were from before they were allowed to sail as a bride on Military Transport to the United States. From this website: http://www.history.navy.mil/photos/sh-civil/civsh-b/brazil.htmhttp://www.history.navy.mil/photos/sh-civil/civsh-b/brazil.htm(with a picture) "In March 1942 Brazil became a War Shipping Administration troop transport, operated by Moore-McCormack. During the rest of the Second World War she made over 30 overseas voyages from United States ports, mostly in the Atlantic. The end of the conflict found her in the Pacific, where she had also operated during part of 1943, and she called at San Francisco in September 1945 for repairs and again in January 1946 before returning to the Atlantic. In March 1946 Brazil was part of the Army's "bride fleet," which brought wives and children of U.S. servicemen from Europe to the United States. She was released in August 1946 for reconversion to civilian service and rejoined Moore-McCormack in May 1948 on the South American route. S.S. Brazil was placed in the Maritime Administration's James River, Virginia, reserve fleet in December 1957 and was sold for scrapping in January 1964."
So your wife and her mother docked at a berth/pier under military control at the port of New York City and not Ellis Island. The "(#8)" in the manifest right after "...Port of New York, N.Y." refers to the page number of the alphabetical listing of "Manifest of Aliens applying for admission to the United States under the Act of December 28, 1945 and of accompanying U.S. Citzen Children" arriving March 07, 1946. Your wife has "[U.S.Cit]" stamped before her name on this manifest.