Walter's mother was called Millicent and she was from Panfield in Essex so this couldnt be his mother. His mother died in 1903, 5 years before his father died in 1908, both died in Essex so this MARY couldnt be Walter's mother!
Mary King's age and place of birth both fit in with the census you have, as does Mary Jane's, apart from the Ann/Jane difference!
I cant find a Mary Cunnah nor a Mary King on the 1881 of the right age either!
Emma