Think this is a likely 1891, David's Marriage cert would confirm. There is a Thomas Edmunds who is a boarder with family in 1901 that fits, looks likely brother.
Victoria Street, Llanwonno, Pontypridd, Glamorganshire, Wales
RG12 Piece number 4415/109/38
William Edmunds Head Married 51 Police Constable, St Athens Glamorgan.
Eleanor Edmunds Wife Married 36 Aberdare, Glamorgan
Mary J Edmunds Daughter Single 24 Domestic Servant Aberdare, Glamorgan
William D Edmunds Son Single 22 Coal Miner Merthyr, Glamorgan
Eleanor Edmunds Daughter Single 17 Domestic Servant Aberdare, Glamorgan
Thomas Edmunds Son Single Male 16 Coal Miner Aberdare, Glamorgan
David Edmunds Son 15 Coal Miner Aberdare, Glamorgan
Gwenllian Edmunds Daughter 12 Hatter Merthyr, Glamorgan
John H Edmunds Son 11 Scholar Merthyr, Glamorgan
Alice M Edmunds Daughter 9 1882 Scholar Merthyr, Glamorgan
Robert Edmunds Son 7 Scholar Merthyr, Glamorgan
Arthur J Edmunds Son 5 Scholar Treharris, Glamorgan
Edith Edmunds Daughter 3 Scholar Mountain Ash, Glamorgan
Sarah Edmunds Daughter 1 Mountain Ash, Glamorgan
Edgar C Edmunds Son 0 Moutain Ash
1901 same family with married dau
https://familysearch.org/ark:/61903/1:1:XSMV-C72