John Grant's biography in VICTORIA AND ITS METROPOLIS: PAST AND PRESENT (1888)gives more detail about John's time at Campbellfield where he planted the first vast area of wheat in Victoria and I can supply much information about his time at Tullamarine, the relationships between the Grant and McNab families, the location of Seafield etc., but I can't recall details of his passage to Sydney and then Melbourne. I also don't recall seeing his parents named so I'll start with his death record. The present Melrose Drive in Tullamarine was the boundary between the shires of Keilor and Broadmeadows so his place of death could mean that he died in the shire of Keilor or that the death was registered in Keilor Village. John's parents may have been cousins.

EventDeath Event registration number12824 Registration year1904
Personal information
Family nameGRANT Given namesJno SexUnknown Father's nameGrant Peter Mother's nameMary (Grant) Place of birth Place of deathKeilor Age92

The story of John Grant's voyage to Sydney and then Melbourne.
THE LATE MR. JOHN GRANT. A NOTED STOCKBREEDER.
The Queenslander (Brisbane, Qld. : 1866 - 1939) Saturday 21 January 1905 p 25 Article