Hi again,
Re the sibling thing - John McKay 1884 had several siblings but all younger than him born between 1885 and 1894 so them having illegitimate child idea doesn't work. (Funnily enough that was how I found Samuel's ancestors, as he was actually the son of his "sister" and was brought up by his grandparents, calling them parents). I have done some investigation around Samuel's siblings - looking for a possible child born around 1890 that could have been my John, but no luck so far.
I don't know where my Granda John was born - have always assumed Glasgow, until this other John McKay came up. I don't think he was a Stornoway native, as family stories state that he went there and met my Granny - she is from there and I have traced several generations of her people.
I did try searching for John MACKIE in the 1911 census - and one came up in Barra - which is in the Western Isles also? States this John Mackie was 22, Ships Carpenter, born in St Cyrus Kincardineshire ....but not that hopeful because of the occupation - I'll pursue this a little further.
My only option in establishing where he came from/who he actually is.....is if someone who knew them in Stornoway may have noted where he came from, or said he came from.......