How can he have arrived in 1839 if he was born in 1840? His age at death seems to suggest a birth in 1832/1833. And if he did arrive as a young child, presumably his father died in Australia, so you need to find records of his father there to see if they tell you the name of his father. What about the marriage record in 1858? Does it name his parents?
There is a marriage of Angus Kennedy to Ann McIntyre in Glasgow in 1823. A daughter Anne was baptised in Glasgow Gorbals in 1825. You can view the originals of these records at
www.scotlandspeople.gov.uk at modest cost.
From the newspaper extracts it seems clear that Angus Kennedy had died before Mary's marriage.
From The Argus, 13 September 1862:
On the 9th inst, at Reilly-street, Fitzroy, Mrs Ann Kennedy, relict of the late Mr Angus Kennedy, aged sixty-one. That puts her birth as 1800/1801, which would fit with a marriage in 1823. There are two deaths of Ann(e) Kennedys in the Victoria deaths index in 1862. Have you looked at either of these?
Also from The Argus, on 18 and 19 August 1857: THE Friends of the late Mr ANGUS KENNEDY,
Joiner, are respectfully invited to follow his remains to the place of interment in the New Cemetery.
The funeral procession to move from his late residence B??h Cottage, 34 Licenter-street, on Wednesday, 19th inst at three o'clock p.m. CROFT and MU??RAY, Undertaker, 82 Madeline-street, North Melbourne. 271 aug 19. There is a death of Angus Kennedy in the Victoria deaths index in 1857. Have you looked at this?