After seeing your later thread
https://www.rootschat.com/forum/index.php?topic=860741.0 and coming back to this one, I wonder if James Campbell McLeod's father was in fact a McLeod at all?
Donald McLeod died in Nigg in 1867 aged 25
mother's maiden surname Fraser.
His widow then gives birth to James Campbell McLeod in 1871.
Twenty years later, James Campbell McLeod gets married, and tells the registrar that his father was James McLeod.
There are various possibilities
(1) He is genuinely the illegitimate son of a James McLeod
(2) He knows that his mother's husband was a McLeod but makes a mistake about his mother's husband's given name
(3) He invents a father to hide the fact that he is illegitimate
(4) Some other explanation I haven't thought of
There is a possibility that Jessie's illegitimate pregnancy might have come to the attention of the Kirk Session of eiither Nigg or Fearn, and if so that that their minutes might provide a clue to the identity of James Campbell McLeod's father. Unfortunately the Kirk Session minutes for 1870 onwards have not yet been made available on Scotland's People, though they do exist, according to the catalogue of the National Records of Scotland
CH2/555/5 Nigg Kirk Session - Minutes (register of doctrine and discipline) 1862-1884
CH2/995/3 Fearn Kirk Session - Minutes and communion rolls and baptisms 1870-1907
(Why, I wonder, was Jessie living with her parents in 1871, using her maiden surname, having left her daughters Catherine and Jessie with their grandmother Janet Fraser or McLeod? I see that her daughter Elizabeth and son David had both died in infancy.)