So William Bowden and James Cash travelled to Brisbane after 1842 and by the time they married the McQueenie sisters in 1849. Queensland separated from NSW in 1859 so their marriages are transcribed as Brisbane NSW.
William did not change his name: he died in 1871 at Laidley Qld: Bridget (Biddy) died Nov 1908 in Roma Qld where they had selected land. (Ancestry.com.au) See also Trove.nla.gov.au
James Cash is a little harder to trace ; this is a possibility ? fo r Qld.
Name: James Cash
Death Age: 66
Birth Date: 1804
Death Date: 13 Dec. 1870
Burial Date: 14 Dec. 1870
Burial Cemetery: Lutwyche Cemetery
Cemetery Plot: MONUMENTAL-RC1-16-62
Other Name: E
Mary McQueeny m. 1 James Cash 2. Edward Cain
Name Mary Cain
Maiden Name McQueeney
Birth Date 1832
Birth Place Drumshanbo, County Leitrim, Ireland
Death Date 29 Jun. 1913
Death Place Petrie, Moreton Bay Region, Queensland, Australia
Cemetery Albany Creek Cemetery
Burial or Cremation Place Albany Creek, Moreton Bay Region, Queensland, Australia
Has Bio? N
Hope this helps.