Hello Frank
I am the Carol you met in Peel. Good to hear that you you've found a few more bits & pieces.
I have also been trying to find the Millars on the 1891 for you without success so perhaps they are in Ireland - although in 1891 many entries in Peel are mis-indexed due to the head of the family being away fishing and some bright spark has assumed that the wives all belonged to the last head specified.
I also believe that there are probably missing entries as I am also unable to find my Kelly great grandparents & their family who should probably be in either Peel or Douglas.
Best wishes
Carol
IOM