Hello Johan,
I hadn't noticed that Robert was married twice - I only knew about his marriage to Jane so thats new to me.
It seems that Isabella, their daughter, moved to Aberdeen after her husbands death. She married John Christie (1835-79) in 1862. He died at Tullynessle, Aberdeenshire.
I found Isabella and her family on the 1881 Census:
78 Shiprow, St. Nicholas.
Isabella Christie, Head, W, 48, washerwoman, b. Cullen, Elgin. (?)
James Christie, Son, Unm, 16, Stone Cutter, b. Inverurie.
Isabella Christie, Dau., Unm, 13, Servant, b. Inverurie.
Charles Christie, Son, 7, Scholar, b. Inverurie.
Anne Christie, Dau., 3, , b. Keigh, Aberdeen.
Isabella died in Aberdeen in 1924.