You do have lots of information but maybe don't realise what you have, what's missing and how (if possible) to find missing bits.
If Catherine was born c1871 (going by marriage certificate) not likely to be Catherine born in 1866. However two Coyle/Golden families are quite possibly related to keep note of anything you find just in case later searching makes the connection.
If Catherine had died in Scotland there would be more information on death certificate. As she died in Ireland all a death certificate will say is: name, date place and cause of death, age at death (as given by informant), occupation, marital status, name of person registering the death. It will not say names of parents/spouse or birthdate/place.
From IGI children (all I could find) for John Coyle and Jane:
1. Sarah born 10 Dec.1864 Aughnacloy dist., Tyrone (mother- Goolden)
2. Catherine born 16 Feb.1866 Augnacloy dist, Tyrone (mother- Goolden)
3. Jame Charles born 26 July 1869 Ireland (mother- Gouldan) [prob. James]
4. Elizabeth born 12 Sept.1871 Co.Tyrone (mother- Goulden)
5. Ellen born 22 Feb.1874 Co.Tyrone (mother- Golden)