Do you think the James McInteer (visitor on 1861 census) is Thomas's older brother? He appears on the 1881 census (Edinburgh)with wife Jessie and one of his children is called Thomas and another, Hugh born in 1867. He seems to have married in Scotland (before 1867) so perhaps you should look at his marriage to Jessie and perhaps find his father and mothers' names?
RosemaryJoan