Gets a little confusing when someone replies off list without noting what they are advising, so apologies if you already have this information. The Brisbane Cemetery information is at http://www.brisbane.qld.gov.au/BCC:STANDARD::pc=PC_899http://www.brisbane.qld.gov.au/BCC:STANDARD::pc=PC_899
There is a possibility there for James Milner and buried with him is a Fanny whodied many years later than James but could be his wife.
BDM records for Qld post 1914 are available on Microfiche. Births to 1919, deaths to 1964 and marriages to 1939. If you live anywhere near a LDS family centre, they would have them, or should be able to order them in for you to check. In Australia they are available at many libraries etc.
Funeral notices for any of the folks you have identified at Toowong may give additional clues as to family members/daughters married names. If you would like me to check for these, let me know which ones. I go to the State library about once a month & they have films of the newspapers - need an approx date to find them, but this is available from the burial.
If you have names of some children that you think may still be living, the australian white pages may help www.whitepages.com.au
Qld death certificates are very informative, although not easy to obtain (due to the idosyncracies of the Qld registry office). Details of how to obtain same & what is available to "anyone" is on their web site. They contain (if the informant knew), parents, children, marriage & burial details plus length of time spent in each Australian State.