Sinann,
Sarah's mother was Elizabeth Bryne Boulger and the marriage in Co Wicklow in 1857 is almost definitely hers.
Siblings were Edmund (B: 1859), Georgiana (B: abt 1861), Hariet (Harriet) (B: betw 1871 & 1873), Henry (B: 1879).
I did have the ship's manifest documenting Sarah's immigration to the U.S., but only page one and not page 2. Page 2 has her place of birth which I have never known before. I assumed it was in Marlborough, not Dublin. That's great to know. I've never been able to find her birth registration.
I think the name of the person listed on or 2 that she was visiting on New York was her sister, Georgiana (Georgina) whose last name then was Scardefield.
Of course, three weeks later she was getting married in Kansas to William Smith.
Her mother's address listed on pg 1 of the document is 27 Essex Quay in Maryborough.
It was great getting page 2 of this document. Many thanks, Sinann!