Very few of the OPR documentys (pre-1855 Statutory Registration) have the names of Witnesses, they are usually restricted to one sentence over two lines, typically- " DATE | John Doe < and Mary Doe> presented a son for Baptism "
Similar extremely brief entries for Banns, with the Marriage date as an addendum or almost an after-thought.
Only three Banns/Marriage records come to mind over the 25 years I have been doing such researches, as having extra information regarding others - but NOT "Witnesses" as such.
One mentioned the Employer's name and location.
Second had the name of the "Guid Man" or Groom's Man, who was standing as Guarantor that the Groom would turn up for the Marriage itself - I think the sum was £100, huge in those days.
The third amounted to a "Pre-Nuptial" agreement so that the money and property belonging to the lady would remain HER PROPERTY at all times; otherwise on marrying, it would transfer to her husband and she would lose all direct control. Relatively lengthy.
The one OPR Death that I have seen is extremely brief-
" DATE | Hannah Aldred, relict of John Tant. "
Another was revealing - but not in the Witness sense.
A lady was recorded as dying on a particular day etc as a Widow oor Relict.
I then found her husband and their only son/child had died on the immediate previous day - all from cholera.
So basically, there are very few Witness Names to be transcribed from those ancient OPRs, in to modern Search Databases, no matter whether the transcription is done by Family Search (LDS), Scotland's People etc.