In general marriage registers prior to 1845 didn?t contain the couples? parents? names. From April 1845 onwards the father?s names were recorded (but not the mothers) and that?s still the practice today. All that canon law required was the couples names and that of their two witnesses. Sometimes you also got a townland or an occupation but sometimes not.
Deaths have been recorded in the civil registers since 1864. Prior to that the only records are church records but unfortunately Presbyterians rarely kept burial records. You might find a gravestone or two though.
From April 1845 onwards marriages were recorded by the church and a separate copy was kept by the civil registrar. You can search for such marriages on the Familysearch site:
https://www.familysearch.org/search/collection/1408347
The civil registration town for Donaghadee was Newtownards, so any birth, death or marriage registered there will show under Newtownards on Familysearchj.
Copies of the church baptism and marriage records are generally held in PRONI, Belfast, though some records are still held by the church and some by the Presbyterian Historical Society. This is what PRONI hold on Donaghadee 1st:
P. 1st Donaghadee Baptisms, 1793-1950; marriages, 1805-06 and 1813- 1936; session and committee minutes, 1783-1826; index of baptisms, 1793-1921, marriages, 1805-1936, and communicants, 1879-1916.
This is what they hold for Shore St:
P. Donaghadee, Shore Street Baptisms, 1849-1966; marriages, 1850-1936.
There are several other Presbyterian churches in the Donaghadee area. For Presbyterians which church you attended was a matter of personal preference and not necessarily the one closest to where you lived. Bear in mind too that for a marriage, tradition was to marry in the bride?s church, after which she?d attend her husband?s. So you don?t always get the wedding in the same church as the children are later baptised in.
None of the records in PRONI are on-line and a personal visit is required to access them.