I have no idea who her mother was. I suspect that she may have her birth cert in her mothers name. Although she names her father on the marriage cert, I do not think this was him. I do have evidence that she was living with that family in 1917, so I have the right man.
I think she may have changed her surname to his when living with them, in 3 rooms, a family of 11. ( which argues with the photo) There was no formal adoption then, you could just change your name, but she did give my father that surname as his middle name, so there is hope!!
What a tangled web!!