Thomas's death certificate states his parents 'not known'. His older brother John's death certificate states his parents as James SMITH and Elizabeth CONWAY. The surname is not clearly written - it is most likely CONWAY though it was actually written more like CEANWAY.
Thomas states that he is from Launceston on his 5th child's birth certificate (in 1898 Victoria). I wonder whether the birth certificate of his 1st child in 1888 Tasmania would also state where Thomas was from. Do you know if Tasmanian birth certificates recorded this level of detail back in 1888?
If I could get a list of all Tas SMITH births from 1859 to 1866 with first name Tho* or John/Jno, and with father Ja*, then I could trawl through it. I assume this would be a long list, given such a common surname!