The Thomas Wallis who was stationmaster at Cookstown was my maternal great grandfather (died 1906) and the Thomas Wallis who was stationmaster at Randalstown (born in 1809, died 1876) was, indeed, his father.
The Margaret Glenn in Kansas Avenue in the 1911 census was the widow of Thomas Wallis of Cookstown, and the Mary "Glannel" Lillie was actually the Mary Glenn, daughter of Margaret and Thomas, who was my grandmother.
The William "Garde" Wallis in the 1901 census was probably a transcription error for William Scott Wallis, who was by 2 years Hugh Malcolm's elder brother. Neither of them are recorded in Cookstown that night, and I believe that they were away at boarding school. That Hugh Malcolm, father of the Hugh Malcolm with the 2011 obit in Toronto, moved to Canada and died in 1957 by family records.
For Julia.n: William Nixon attended the 1906 funeral of the Cookstown Thomas Wallis and was listed as his son in law.
For agahadowey: Margaret Lockyer died in Belfast in 1976. Isabella Catherine married Robert Henry Gilliland and died in 1948. I knew their daughter Patricia, who married David Hodges. She died of Alzheimer's, maybe 10 years ago.