Family history detective skills

Family history research involves patience, good computer skills and above all, excellent detective skills.
There is a little poppet buried in the Melton Cemetery by the name of Mary Amelia Mitchel. She died in 1889, aged 6. Her father managed a station at Rockbank.

For the month of August, Victorian Births Deaths and Marriages has a reduced fee to download PDF copies of certificates. (Interestingly, the Tasmanian equivalent provides certificates prior to 1900 for FREE!!!!!! I mean, all you're doing is downloading a PDF.)

Anyway I wanted Mary's certificate to see what her cause of death was. Her mother, Mary Hamilton Allan was my 3rd great aunt, and Mary my 1st cousin 3x removed.

When you search for a record on Vic BDM you get basic information, you have to pay for the certificate to get more detail. (In the past I paid for a certificate that proved not to be my ancestor. GRR.)
Mary Amelia's brief has her mother's maiden name as WILSON, her mother was Mary Hamilton Allan. The little doubt train starts rattling around in my head. Is this the right child? I ordered the certificate anyway.

The certificate doesn't say her mother's maiden name was WILSON, it says her father's surname was formerly WILSON (that was his mother's maiden name).

Another misleading piece of information that required navigating.

Poor little Mary Amelia died from diphtheria.