There's a John John Owen & family living at Glan Gwyrfai on the 1901 census and completed a Welsh census form. One daughter is called Ellen (could be Nellie).
RG RG13 Piece:5274 Folio:41 Page:4
Reg. District:Carnarvon
Sub District:
Carnarvon
Parish:Waenfawr Enum. District:15
Ecclesiastical District:
Bettws Garmon & Waenfawr
Address:Glan Gwyrfai, Waenfawr
County:Carnarvonshire
OWEN, John Head Widower M 49 1852 Slate Quarry Man
Waenfawr, Carnarvonshire
OWEN, Robert Son Single M 25 1876 Slate Quarry Man
Waenfawr, Carnarvonshire
OWEN, David Son Single M 23 1878 Slate Quarry Man
Waenfawr, Carnarvonshire
OWEN, Ellen Daughter Single F 19 1882
Waenfawr, Carnarvonshire
OWEN, Dorothy Daughter Single F 16 1885
Waenfawr, Carnarvonshire
They are on the 1891 census:
RG number:RG12
Piece:4661
Folio:116
Page:13
Reg. District:Carnarvon
Sub District:Carnarvon
Parish:Llanbeblig
Enum. District:18
Ecclesiastical District:Waenfawr
City/Municipal Borough:Carnarvon
Address:Glan Gwyrfai, Llanbeblig, Waenfawr, Carnarvon
County:Caernarvonshire
OWEN, Joh(n) Head Married M 32 1859 Slate Quarryman
Llanbeblig, Carnarvonshire
OWEN, Margaret Wife Married F 36 1855
Llanwnda, Carnarvonshire
OWEN, Robert Son M 15 1876 Slate Quarryman
Llanwnda, Carnarvonshire
OWEN, David Son M 13 1878 Slate Quarryman
Llanbeblig, Carnarvonshire
OWEN, Ellen Daughter F 10 1881
Llanbeblig, Carnarvonshire
OWEN, Margaret A Daughter F 8 1883
Llanbeblig, Carnarvonshire
OWEN, Dorothy Daughter F 6 1885
Llanbeblig, Carnarvonshire
There is also another Owens family in the schedule before this living at Cyrnant Lodge Glangwyrfai head of family a Mary Jones who is a widow born 1820 Llanbeblig, with Davis Owen (lodger) and his wife Elizabeth born 1856 Llanbeblig and daughters Ellin A b 1876 and Mary 1882.