Here is a problem - (MacHamish) Captain Alexander Gunn of Badenloch was born around 1683. Fine. But his second wife was Anne / Ann Rose and she was born 12 September 1733. That's a fifty year age gap. I don't have the exact date of the wedding but let's say 1753 when she was twenty - that would mean her husband was seventy. I would have thought such a gap would have been remembered as it was not common then, nor today.
Why would she marry? Captain Alexander was not much of catch as he has lost a massive amount of money due to a huge legal battle he had with the Sutherland estate. Anne's younger sister Barbara married a Reverend only slightly older than her; why did Ann / Anne not do the same?
There has to be a reason for marrying someone fifty years your senior...