I am now in possession of a copy of Captain Fraser's Collection (fac-simile reprint of the 1874 Edition).
I wonder if the reproach made by John Lorne Campbell to his version of "Mo run geal og" apply to both editions -1816 and 1874.
The 1874 edition gives, in fact, two versions of that tune:
-page 85: the 1st version (which I used for my arrangement)
-page 96 (Chapter "Additions from original 1816 Edition"): a 2nd version which is beautiful and poignant and , by far, superior to its predecessor. It is now the background music for the page

http://chrsouchon.free.fr/morungea.htm

(where your different remarks are embodied, making of this page one of the best documented of the site).