I am a GGgranddaughter of Hiram E & Annie Elizabeth,My Great Grandfather was George Albert Picton Pierce,my Grandfather was George Hiram Emery Pierce.I have recently started a family tree& have also been prompted to follow the Maine connection,of Hiram E born in 1838 , he is the son of Hiram born in1817 & Deborah born in 1816. I have no further conclusive information, I haven't been able to obtain a death record . If your Hiram died in 1901 in Balmain North there are no parents listed on that registration, so I can't help with Mary Delaney.
Cheers