Scenario could be ...
In 1877, Mary Ann Hill, single woman gives birth to Emily Jane HILL
In 1879, Mary Ann Hill, single woman gives birth to Elizabeth Ann HILL
She meets John Ball and lives with him as man and wife on census in 1881, the 2 girls listed as BALL.
The couple have a child Harry Edwin 1881
Marry in Bristol in June Q 1883
Have another child, Sarah Frances in Dec Q 1883.
The 4 children all Baptised, 15 May 1884.
Meanwhile, still searching.