Something, somewhere, doesn’t make sense.

The most popular ten female names in Ireland of the 19th century, in descending order, were Mary, Bridget, Margaret, Ellen, Catherine, Kate and Annie. Kelly was the most common surname after Murphy. So Mary Kelly is the Irish equivalent of John Smith. Of course that doesn’t mean Mary Kelly wasn’t her birth name, but if she wanted to hide it’s easier amid a shoal of Marys and a herd of Kellys.
And she certainly recoiled against the moniker, stating she was really Marie Jeanette and not plain Mary Jane.
And just to add to the anonymity she says her father's name is John – or John Smith if she were English. I don't believe her.
She did state she came from a well to do family, this is I do believe. “She was an artist of no mean degree.” All middle class and upper girls were taught drawing, painting, sewing and singing as one of their accomplishments. The middle classes became interested in revolutionary ideas some, if Irish, involved the Fenians, others explored socialism.
Barnett claimed Mary Kelly had six or seven brothers living in London depending how we interpret his statement: There were six brothers living in London, and one was in the army. One of them was named Henry.
Six or seven males, sharing the same surname, shouldn’t be difficult to find!

Mary told Julia Venturney, a German charwoman who lodged opposite her in Miller's Court, that a man called Joe continued to visit her after she had taken up with Barnett. But we know next to nothing about this or any other of Mary's early relationships. Our sources, too, leave important questions unanswered.
Why did Mary leave Wales for London?
What was the truth behind the stories of the West End brothel and that mysterious jaunt to France?
And why was a girl of Mary's youth and reputed good looks thrust into the desperate squalor of an East End lodging house
Mary had a trunk of good quality clothes, which she collected from a French woman in The West End. As she owned expensive clothes, she could have sold some garments and worn others, which would have granted her access to a better class and therefore richer punters. But she didn’t do that. She returned with her trunk to Ratcliffe Highway.
Why did she return to Ratcliffe Highway?
If we compare Mary Kelly to Emily Dimmock, a woman of a similar age and livelihood, why wasn't Mary taking more money for her services? Why did she sell herself short? Emily Dimmock earned at least two guineas in three days. Mary Kelly couldn't pay her rent ...

Something, somewhere, doesn’t make sense.
Sherlock Holmes: Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.