You've lost me a bit with your last post!
This is how I see the possible scenario:
James Hextall son of James and Martha Hextall b Sneinton 1877.
He marries Mary Ann Henton in 1895; she has a baby and sadly both she and the baby, mary Jane, die in 1896.
James is then alone and a widow until he marries Annie Newbold in 1909. He then dies in 1919.
So you can see that there were 13 years (1896-1909) when James was single, during which time, if my hypothesis is correct, he could have met Emma and they had a child together - James jnr, b Sneinton 1901. Because his parents weren't married, James jnr's birth was registered under his mother's surname (which we don't know). When his parents split up, his mother kept using the Hextall name rather than revert to her real name, and so did James.
I don't know how you could prove this.