I too have Doherty's from Co Donegal, a lot I believe from Malin Head area.
You mentioned Nicknames, and I have been trying for years to find out if my great grandmothers name Susan "White' DohertyIts the White I'm interested in, have never seen that as a nickname, but neither have I seen it as a middle name for a Doherty. Don't think she had been previously married.So I'm wondering if anyone has heard of White as a Nickname for Doherty family.
Susan was born about 1845, married James O'Donnell also bron in 1845, . They married at the Sacred Heart Church in Carndonagh in 1865/66.Their children were : Patrick 1867, John 1868, Neil 1871, Mary Ann 1873, Maggie 1875, Denis 1878, and Philip 1880.
I hope one day to learn who Susan's family(parents sibblingswere, and where Susan was born. etc.