Hi Toni,
Queensland BDM indexes are online
https://www.bdm.qld.gov.au/IndexSearch/queryEntry.m?type=bir...You can purchase certificates from the Qld government website.
You already seem to have a reasonable amount of info so I don't know what you mean by 'starting' your family tree? I suggest that you limit each post to a person or couple and ask specific questions about each one.
Debra