I wonder if this is Isaac's birth - given they are under a wierd spelling mix of Cambpell and Kemble in 1891
Isaac Campbell
Q4 1866
Cardiff Vol 11a, p207
similarly there's this outside possibility for MAry Ann
Mary Ann Campbell
Q3 1864 Cardiff Vol 11a, p221
I found some newspaper reports for an Elizabeth Kemble, with convictions for pilfering a shop till in 1876, aged 14, and two for theft from jewellery shops in 1881, an 18 yr old charwoman. There's an ELizabeth aged 18 in Cardiff prison on the 1881 census, born Aberdare, as well as the one with Isaac and Catherine (who is a charwoman!!). it's noticeable there's only on Elizabeth Kemble on 1871, and one birth in Glamorgan of an elizabeth Kemble in the right period, in Merthyr Tydfil district.