The second reference appears to be also in Island Magee. It is in the newspaper of 5 October 1798 (page 3) and simply reads, "notice wife = McIllhagoo, Jennet = Wilson, Jennet goods caution credit + Island Magee 3 = Wilson, Patrick". At present I don't understand whether everything after the first Jennet is relevant and I think I will have to look up the original paper when I next go to Belfast. Hopefully it will help us decide whose wife Jennet was. It may well be that she was the wife of Nathaniel.
The third reference was in the paper 6-9 November 1781 (page 3) and I believe it takes us back a generation in the townland of Maxwell's Walls in the parish of Connor. It is the intriguingly brief notice reading "Stray beef cow = McIllhago, William + Connor 8". It looks as if William, who must have been born before 1760 could have been the father or grandfather of the group of men farming in Maxwell's Walls early in the 19th Century, including Henry, John and William. Father or grandfather William must have had a problem with one of his cows! Again, we may have more information when we see the full report in the paper.