Hi Carol,
I also have your Mary Ann (married Henry Milner) as the daughter of George Cannon (convict on Mangles) and Mary Ann Dean (convict on the Majestic). She had a daughter, also called Mary Ann. I am not sure how much information you have, but I have a bit. Feel free to message me and we can swap information if you are interested.
Interestingly, it seems that George Cannon's son (Thomas, who is my relative), married Mary Louisa Young, who was first married to Bruce Gunn (the one who then seemed to marry his sister, Mary Ann) They all appear to have lived in Paterson St.
Cheers!