There is an extracted record for that marriage on the 8th as you found - since Jane Braid was I think d/o a successful douglas coach owner it would probably have been in the local paper so check there.

The second part I don't fully understand - if you mean that the actual records disagree with info provided off the IGI then welcome to the real world - the IGI with patron submitted entries is TOTALLY unreliable - you cannot distinguish between correct replacements and fictitious nonsense - the mormons fouled up what was once (check out the microfiche) a quite accurate transcription of the official copy with, to put it politely, junk.