There was a Thomas Edward HARDING born in Queensland Country on 12/2/1911 with only the mother May HARDING listed as a parent(no father listed)(Reg.No.1911/001682).
I was unable to find this person on the 1934 Electoral Roll(which is searchable) as either HARDING or DALY.
I checked the Queensland births on microfiche for children of Daniel DALY and May HARDING for the period of 1915-1919,and there were none registered.
If your Daniel DALY who died in 1930 is the correct partner for May HARDING,then perhaps the "Transmission of Death by Real Estate" index may help to see if he had property and may have had children who were not registered.
As for Electoral Rolls,if your Daniel was born 1884,he would not have been on the Electoral Roll in 1903,but should have been on the Electoral Roll after that.On the 1913 Electoral Roll(which is searchable)there are only two Daniel DALY entries:
Daniel DALY Coventry Street Maryborough(Wide Bay division,listed as an engine driver.)
Daniel DALY at Sarina in the subdivision of Mackay,division of Herbert,listed as a farmer.
On the 1922 Electoral Roll(which is searchable)there is only one Daniel DALY listed at Abbeyville,Morris Street Paddington,subdivision of Ithaca,division of Brisbane listed as an engine driver.
I would have to go through the Electoral Rolls for Brisbane to see if your Daniel was listed with May in 1915 and try to follow them through later Electoral Rolls(maybe only 1917).