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This is my first time posting in Ireland. I live in South Australia. I really have no clue how to find out things in Ireland.
My triple great grandmother Mary Crimeen emigrated from Ireland to South Australia by 1854; probably in 1851 on the ship Hydaspes. There are many variations on the spelling of her surname (Cremins on her marriage registration in South Australia) but many of her descendants have "Crimeen" somewhere in their given names.
Her sister Sarah Crimeen died in South Australia in 1911. In her will she left money to all of Mary's children and also to "my sister Eliza O'Brien of The Copse County Wicklow in Ireland". In her will Sarah referred to all her married female beneficiaries by their married surname.
Sarah had another sister Bridget Crimeen who died in South Australia in 1906.
From their ages at their dates of death, Sarah was born c1840, Bridget c1834, and Mary c1836. So presumably Eliza was born in a related time range.
Andrew Crimeen born c1824 and Elizabeth Crimeen born c1820 who emigrated on the same ship are siblings of each other and related in some unspecified way (they are buried in the same plot as Bridget and Sarah).
My question is: Can anybody find out anything about this family in Ireland? I am thinking that the best lead is "my sister Eliza O'Brien of The Copse County Wicklow".
Thank you for any help you are able to provide.

I haven't posted to a County board before so I hope I am within etiquette. I don't really know anything about finding out events in Wales.

I am looking for some marriage and burial information about a distant cousin Lillian Veronica Ellis nee Horgan born 1917 in Australia died July 16 2003 in Wales. According to the England and Wales Death Registration Index 1837-2007 in familysearch she died in Cardiff, Glamorganshire. I would also like to know where she is buried.

She moved to Wales (or possibly England I'm not 100% certain but in any case she ended up living in Wales) some time in or after the late 1960s and met her husband there.  She was Catholic if that helps.

Also I am told she was married to a Roger Ellis who taught music, possibly a university professor, who lived in Wales. If possible I would like to know when they were married. I can't be certain he is not still alive but I believe it to be very unlikely because most likely he was older than her.