Do you have the 1900 marriage cert? If not, you'll need to get a copy in order to get the names & occupations of both fathers. Lapham isn't too common, so I'll have a look around, but Thomas without extra info is a no-go.
There's a likely looking birth reg
Esther Ann Lapham sept qtr 1882 Neath vol 11a pg 590
1901 census 7 Cribbs Row, Neath RG13/5058 folio 80 pg 19
William Thomas head mar 20 coal hewer
Esther Ann wife 18
both born Neath
1891 13 Zoar Road, Neath RG12/4462 folio 145 pg 7
Henry Lapham head mar 41 moulder b. Pembroke
Catherine wife 40 b. Rhydyfelin
Elizabeth Jane Brittle dau single 20 b. Pontypridd
Sophia Brittle dau 18 b. Aberdare
Jane Brittle dau 15 b. Aberdare
Alice Edwards Lapham dau 11 b. Mountain Ash
Esther Ann dau 8 b. Neath
William Henry son 3 b. Neath
marriage of parents
Henry Lapham march qtr 1879 Merthyr Tydfil vol 11a pg 410 with Catherine Brittle only other name on the page
1881 1 Canal St, Neath RG11/5341 folio 10 pg 13
Henry Lapham head mar 31 moulder b. Milford Haven
Catherine wife 31 b. Rhydyfelin
Alicia E dau 12 months b. Mountain Ash
Elizabeth Jane Brittle step dau 10 b. Pontypridd
Sophia Brittle step dau 8 b. Aberdare
Catherine Brittle step dau 7 b. Aberdare
Jane Brittle step dau 5 b. Aberdare
Henry's birth place in 1881 leads to this family
1851 Cross St, Milford HO107/2477 folio 81 pg 15
William Lapham head mar 31 moulder b. Ireland
Jane wife 26 b. Pembs, Haverfordwest
Ann Edwards dau 6 b. Carmarthen
Henry Lapham son 1 b. Milford
Jane Lapham dau 2 months b. Milford
marriage of parents
William Lapham sept qtr 1847 Carmarthen vol 26 pg 620 with Jane Edwards on the same page
The Laphams are in Carmarthen in 1861 and there are more daughters including Alicia & Esther, familiar names from Henry's family.