Catherine Agnes Dillon b abt 1818 Liverpool and possibly her sister Mary Ann Dillon

Hi....I am helping someone in Australia who is trying to find info on
Catherine Agnes Dillon born around 1818 in Liverpool...on Catherines marriage certificate to Thomas Gray in november 1838 it has
father Patrick Dillon
witness , Mary Ann Dillon...so possibly Mary Ann Dillon is her sister...we have found out that Patrick Dillon married Ellen Hanlan...so we know Catherines parents and possibly a sister ....Catherine and Thomas emigrated to Australia in July 1839.....we are trying to find
Patrick Dillon
Ellen Dillon
and possibly Mary Ann Dillon....on the 1841 census and any other family...they lived in Roscoe street of Leece Street.....cheers....allan