Common-law wife

With a new snippet of information (I may use it for the title of my book) I am 100% convinced Bridget Kelly of Brymbo knew THE Mary Jane Kelly. I am also certain John Davies of Brymbo (died 1880) was the man Mary Kelly claimed she married. What I am not sure of is that Mary Ann Kelly of Brymbo, and Bridget's sister, is THE Mary Jane Kelly.
The 1881 census states she is still with her family. Not that that discounts her; people lie, or are mistaken.

My gut reaction is that The Mary Kelly was a common-law wife. If I discount Mary Ann Kelly, I'm left with three possibilities, which means I'll have to rewrite chunks of my story, but hey ho. After this I will place Jack The Ripper, Mary Kelly, and all his victims firmly in the out tray and write on a cheerier subject, a dystopian adventure.
I've written approximately 70,000 words. At this rate I'll have written 200,000 words and she'll have just left Ireland.