Marriages were regulated and the information collected included, the age and occupation of the Bride and Groom, their place of birth, the name and occupations of the Bride and Groom's father and any witnesses present. Unfortunately much of this information was not recorded.
Spellings have not been changed and are as the original record. Precise spelling is really a very modern phenomenon so it is quite typical to have records for the same family appear under a variety of spellings. "Grady", for example, could just as easily be spelled "Gready" or "O'Grady". A first name could easily be listed as a nickname, not just in the more "formal" form. "Brigid" could be Anglicized as "Bridget", or appear as one of its nicknames, either "Bridie" or "Delia".