I guess you are aware that there is not a birth of Catherine DOYLE or FANNING born 1865 to Johanna DOYLE or FANNING registered on the Vic indexes.
Using offline resources, there is not a birth in that area to anyone of the surname FANNING or DOYLE. at or around that year.
To get help, or a bit of a start on this, you need to start from what you know and work backwards.
So, are you talking about your mother’s side or your father’s side?
Depending which side, what were the names of their parents.
You can get assistance to find the further details but I believe you are starting at the wrong place

There are people and resources who will do their best to assist if given some concrete information.
Sue