Derek,
Here’s Sarah’s probate abstract:
The Will of Sarah Ellen Letitia Morrison late of Collinview Belfast Widow deceased who died 26 September 1873 at same place was proved at Belfast by the oath of Mary Morrison of Collinview Belfast aforesaid Spinster the sole Executrix.
The will itself is on-line on the PRONI wills site, and mentions 3 daughters Mary, Sarah & Hessie. Hessie was in Shanghai at the time the will was written (1873).
Sarah was 57 when she died in 1873. Her death is in the Belfast Newsletter for 27.9.1873. It says: “At 71 Colin View, Lisburn Rd, Belfast, after a lingering illness, Sarah E L Morrison, relict of the late Robert Morrison, of Belfast. Her remains will be removed for interment in the family burying ground, Ballylesson, on Monday morning. 29th inst at ten o’clock. Friends will please accept this intimation.”
That led me to what must surely be Robert’s death registered Belfast 21.9.1870, aged 48. Reported in the Newsletter of 23.9.1870: “September 21st, suddenly. Mr Robert Morrison, aged 48 years. His remains will be removed from his late residence, 14 Albion St, Belfast for interment in the family burying ground, Ballylesson on tomorrow (Saturday) morning at nine o’clock. Friends will please accept this intimation.”
You can view the original death certificate on-line on the GRONI website, using the “search registrations” option:
https://geni.nidirect.gov.uk
You will need to open an account and buy some credits. It costs £2.50 (sterling) to a view a certificate.
Your Morrison family were gone from Colin View by the time of the 1877 street directory:
http://www.lennonwylie.co.uk/ccomplete1877.htm
Statutory registration of marriages started in Ireland in 1845 (for non RC marriages). I searched 1845 – 1860 but did not see Robert & Sarah’s marriage. Suspect it may have been before that, in which case the records may not be on-line anywhere. We’d to know the church they married in to try and trace it.
I looked for Sarah & Hessie in the 1901 census but could not spot anyone that fitted. (Hessie may of course still have been overseas). Sarah is a fairly common name and so hard to trace.
I found a marriage for Mary Morrison in 1874 to Moses Haslett. Note that the father was a clerk rather than newspaper editor:
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1874/11242/8122580.pdf
Here’s that family in the 1901 census. A useful piece of information is that Mary was born in Coleraine, (which is actually in Co Londonderry, not Antrim). So you would need to search church records there for her baptism as it’s before the start of statutory birth registration in Ireland (1864).
http://www.census.nationalarchives.ie/pages/1901/Down/Ormeau/Delhi_Street/1209669/
I think Moses died in 1909:
https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1909/05454/4526520.pdf
Here’s 4 of the Haslett girls in 1911. I’d suspect their mother had died, but haven’t checked.
http://www.census.nationalarchives.ie/pages/1911/Down/Ormeau/Ava_Street…
Hope this helps you with your research.