that seems to have worked out then.
Here's the rest of the census info
1881 census 11 Lewis St, Abersychan RG11/5252 folio 56 pg 45
William Williams head mar 58 tin worker b. Newton
Margaret wife 53 b. Goytrey
William son 25 puddler b. Trevethin
Thomas son 17 boot clicker b. Trevethin
Thomas Davies boarder unm 51 tin worker b. Goytrey
1891 11 Lewis St RG12/4362 folio 145 pg 31
William Williams head mar 68 stationary engine driver b. Mon, Buckholt
Margt wife 63 b. Goytre
Herbt Jones loder 15 apprentice boot clicking b. Hampshire, Aldershot
William & Margaret noted as speaking both English & Welsh
1901 11 Lewis St RG13/4946 folio 17 pg 25
Wm Williams head widower 71 stoker at stationary engine b. Mon, Buckholt
12 Lewis St has a widowed Ruth Bryant with some of her children & I'm pretty sure that is Sarah Jane's sister.
William gives his place of birth as Welsh Newton or Buckholt Monmouthshire. Now, Welsh Newton is actually in Herefordshire. Buckholt is on the border, but I think was in the parish of Welsh Newton at the time
https://en.wikipedia.org/wiki/Buckholt,_MonmouthshirePossible baptism for William
https://familysearch.org/ark:/61903/1:1:NR8P-C8VParish baptisms for Goytre are online, but I can't see anything likely for Margaret. There is an illegitimate Margaret Davies bp in Feb 1829, but it looks like she's buried a couple of weeks later. I can't find parish baptisms for William & Margaret's children, so it's possible they were non-conformist, quite likely Baptist as that's where Sarah married.