Where have you sourced your information? The indexes show the following
Marriage in Victoria
BOWDEN Thomas George Born North America
MOORE Minnie Born Carlton
1890 Reg#9167
Birth
BOWDEN Irene Evelyn
Father Thomas George Mother Minnie MOORE
At Bunyip South 1896 Reg#26106
There are numerous
BOWDEN birth registrations with the mother's name
Bessie MOORE.
Birth registrations include the people named in the death notice.
http://trove.nla.gov.au/ndp/del/article/22761980BOWDEN.—On June 28, at Caulfield . Repatriation Hospital, George Thomas Bowden, 13 Malcolm street; Bentleigh, late of 66 Page street. Albert Park, loving husband of the late Bessie Bowden, loving father of George. Leonard (deceased).
Irene (Mrs. Marcon), Dora (Mrs. Doig). Lawrence, Albert, Beatrice (Mrs. Millar), late 13th F.C.E.. 1st A.I.F. -So dearly loved, so sadly missed.
Cando