Aumarire, I always go for the simple explanation (Occam's Razor!) and so have never doubted that there's only one Mary Ann/Marion/Marian ever since we first came across her BALLI & CALDWELL connexions back on Page 6

Her date of birth is something which might or might not be able to be resolved.
Perhaps Lu will be able to have a more relaxed look at the Fiche (I think she said that she found Mary Ann at 2 minutes to closing time!).
I know that, for one set of my Irish lot who arrived in Port Phillip in 1841 as Bounty Immigrants, the fiche included a detailed report about the journey and the passengers. It lists my family with ages, occupations, religion, whether able to read and write (not too reliable! - my Ggma Julia, listed as Judy, aged 2 was said to be able to read and write!!), wherefrom, and the bounty paid.
The report included a reference to the number of deaths (7) and the number & sex of births (5 females & 1 male) during the voyage.
Whether it specifically named who died and who was born in the individual entries I don't know - it didn't involve my lot and I have only a partial transcription of the report made about 8 years ago (why didn't I copy it, eh!).
Over the course of this thread, we've seen varying departure and arrival dates for the 'Alexander'. And we've seen Mary Ann as 1 on the passenger list on the PROV, and 7 weeks from Lu. And we don't know whether those are ages at departure or on arrival. Perhaps there is further information to be found on the fiche.
Now a couple of other thoughts.
1. Charles Leslie PARKIN b 1893 - that's a long gap from the previous known births (Edith & William John in 1881).
Has anyone found any between 1881 and 1893? I can't check the index but am wondering ... (shades of Jane Elizabeth AYLMORE/HEASMAN/ANDERSON?).
A David
Leslie QUICK, son of Rachel's daughter Ann Amelia PARKIN and John William George QUICK, died 1978 age 63.
2. We don't actually have any proof that William R HEAS(E)MAN who m 'Harrul' J NEWBY in Wellington NSW in 1878, and died in Wellington NSW in 1897 is the son, William Richard, of William HEASMAN & Jane Elizabeth AYLMORE, do we. It's the only time Wellington came into the picture. William's parents were not named in the death index. His age on the headstone inscription is 56 (gives dob of ca 1840) whereas 'our' William was bap 1846 and was said to be aged 9 on the 1856 Orphan School petition. And there is another HEASEMAN (Henry d 1858 aged 76) in Wellington.
JAP
PS: Pls give a yell everyone if I've left out anything major in the re-posted summaries. I know I've found some myself - I lost bits in the cutting & pasting, esp in making 2 parts into 3.