Will deal with the 'Scottish' problem first.
"There is some indication they may have come over from Scotland. I can find Hugh in Scotland at age 14, but no other sign of them." and "There was a rumor that the family could have come from Scotland, and I found Hugh born there about 1840, that might have worked age-wise."
"How did you find Hugh in Scotland as wondering if is descended from John who went from Ireland to Glasgow,whose father was also called Hugh born 1790?" and "Within the family there is rumour that he is descended from someone in Maybole,Scotland.Hugh b1837 is listed in the 1851 cencus as being born in Ireland but living in Maybole so this seems to be the correct McIlfatricks." and "Unconfirmed that the family came from Scotland to Ireland. When checking Scotland records I found a 1851 census from Maypole, Ayrshire with parents John and Helen McIlfatrick, with children James 31, Jane 18, Mary Ann 16, Hugh 14, Sarah 11, William John 9."
This Hugh McIlfatrick was the son of John McIlfatrick/Kilpatrick (born c1797 Crossland) and Eleanor Gilmore (born c1802 Boveedy). The family went to Maybole, Scotland bet.1842/1851 and then on to Victoria, Australia. In the 1851 Maybole census you will notice 3 young men from Ireland lodging in the household- one of these, John Logan, married John and Eleanor's eldest daughter Jane and they went to Australia in 1862.