Searching for John O'Neill's family

Hi

 My name is Madeleine and I live in South Australia. My great grandmother was Eliza O'Neill. She was born in about 1862. She was married in Adelaide, South Australia in 1883. She had at least 2 sisters who came to Adelaide too. One was called Mary, born in about 1864, and the other was Annie (Ann), who was born in about 1858. We believe they were all born in County Clare. 

Eliza, Mary and Annie O'Neill were all married in the same Catholic church in Adelaide, South Australia in 1883, 1889 and 1894, respectively.

Their marriage records all show that their father was John O'Neill from County Clare. We think they may have come from Ennis, but we have no proof of that. We can't remember whether that information was passed down within the family.

An Adelaide newspaper notice for Annie's marriage, reported that she was the 6th daughter of the late John O'Neill of County Clare. If their birth dates are all correct, that would mean John O'Neill had 8 daughters!

The alternative scenario, is that they lied about their age, to get sponsored to SA, which apparently was quite common at the time. Alternatively, maybe they were second cousins, thier fathers (both John O'Neill), being first cousins.

We believe the sisters came out to South Australia in the late 1870's or early 1880's.

Annie may have come out in 1880 on the ship 'Corona' and called herself Anastatia.

If anyone can help find my great grandmother's family, my 90 year old father and I would greatly appreciate it. :)

Sincerely

Madeleine