Hi having same problem locating James/Elizabeth, but Jessie on the 1891 is aged 18 b Neath shown as Sister in Law to a William & Helen Derrick in 1901:-
Marriage 31st December 1894 Aberavon
William Derrick 20 occ Fishmonger Father William Derrick occ Fish Monger
Ellen Jane Morgan 21 Father James Morgan occ Tailor
In 1901 the couple plus Jessie are at 3, Hopkins Place, Neath
Census Ref RG13/5058/60/15
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