I have also been searching for living relatives and it is soo difficult
The following may help but all information needs confirmation:
I looked at you Emily's family in 1901 and 1911 - Samuel is listed in the baptisms on
www.familysearch.org as born to Henry WILLIAMS and Mary Anne KANE on 09.Aug.1880
As he was still single in 1911 I looked for marriages after that (his being a more unusual name)
There is one listed as:
Dublin North Jan-Mar 1913 Volume 2 Page 464
(this is the reference can be used to order the certificate)
There is also a death registered:
Dublin North Jul-Sep 1939 Volume 2 Page 222 aged 54 (age slightly out but not unusual at the time)
If this is correct his death certificate possibly could help place if indeed he married and where he was living
Also Sarah could have married between 1901 and 1911 or be one of the three children that died.
This is a possibility if she married
Dublin North Jan-Mar 1903 V2 P531
If you check the other famly members you may find information this way leading you to obituaries and more current information.
The register of electors is online for Dublin in 1939 just mentioned may also help place them and it is also available on microfilm in Pearse Street Library for further years up to 1963