I believe your William had a half-brother, William H. MOORE chr 24 Jan 1830, illegitimate son of William MOORE (1798) & Mary CORTEEN (my 3x ggrandmother)
Christened as William CORTEEN (sic) s/o W. W. MOORE & Mary CORTEEN 24 Jan 1830, Maughold, IOM
1841 Census: Aged 12, living with mother and step-sister, in Kissack household, on Thallooqueen, Maughold, IOM.
1851 Census: Farm Servant (20 yrs) for Edward Christian, Balldromma, Maughold, IOM. ?
1881 census:
William MOORE Head M Male 51 Isle of Man Iron Miner
Frances MOORE [nee KENDAL] Wife M Female 43 Hensingham, Cumberland, England
Ben MOORE Son U Male 17 Hensingham, Cumberland, England Iron Miner
Isaac MOORE Son Male 13 Millom, Cumberland, England Scholar
Joseph MOORE Son Male 11 Millom, Cumberland, England Scholar
John H. MOORE Son Male 8 Millom, Cumberland, England Scholar
Kendal MOORE Son Male 6 Millom, Cumberland, England Scholar
Francis R. MOORE Son Male 3 Millom, Cumberland, England Scholar
Jane MOORE Daur Female 8 m Millom, Cumberland, England
Dwelling 36 Lord St
Census Place Millom, Cumberland, England
Family History Library Film 1342253
Public Records Office Reference RG11
Piece / Folio 5196 / 112
Page Number 59
1901 census: William Moore 72 Isle Of Man Cumberland Millom Iron Miner Iron Ore
I believe Margaret married Harry HURCOMBE
1881 Census:
Henry HURCOMBE Head M Male 49 Bampton ? (N S), England Carter & Green Grocer
Margaret HURCOMBE Wife M Female 41 Maughold, Isle of Man
Sarah Ann HURCOMBE Daur U Female 15 Maughold, Isle of Man
Willm.Henry HURCOMBE Son U Male 14 Maughold, Isle of Man Bakers Apprentice
Eliza Margt. HURCOMBE Daur U Female 13 Maughold, Isle of Man Scholar
Emily Jane HURCOMBE Daur U Female 12 Maughold, Isle of Man Scholar
Joseph Thos. HURCOMBE Son U Female 4 Maughold, Isle of Man
George Alfred HURCOMBE Son U Male 8 m Maughold, Isle of Man
Dwelling 4 Quay
Census Place Maughold, Isle of Man, Isle of Man
Family History Library Film 1342345
Public Records Office Reference RG11
Piece / Folio 5600 / 64
Page Number 26
I believe this is Thomas in 1881
Thomas MOORE Head M Male 34 Isle of Man Carter & Dairyman
Jane MOORE Wife M Female 31 Isle of Man
Ann MOORE Daur U Female 9 Isle of Man Scholar
Thomas MOORE Son U Male 7 Isle of Man Scholar
William MOORE Son U Male 5 Isle of Man Scholar
Robert MOORE Son U Male 3 Isle of Man
Infant MOORE Son U Male 1 m Isle of Man
Dwelling 6 Dale St
Census Place Maughold, Isle of Man, Isle of Man
Family History Library Film 1342345
Public Records Office Reference RG11
Piece / Folio 5600 / 113
Page Number 2