Hello everyone! I am new here and this is my first post, so please bear with me

I am searching for my missing family. My great x 3 grandfather was Charles Robertson, born 1809 in Laurencekirk to John Robertson and Elizabeth Paterson. He had at least two siblings, Allan Grey Robertson and Betsey Emslie Robertson.
Charles married Ann Falconer of Fetteresso, she was born circa 1810. They had several sons:
Allan, born circa 1837
James, born circa 1839
Charles Jr., my great great grandfather, born circa 1843 moved to South Leith
John, born circa 1846, died 1898
Thomas, born circa 1848,
David, born circa 1852
Thomas and David were born in Aberdeen. All others were from Kincardineshire.
John was an Army / Chelsea Pensioner, and married Helen Gaiter, they had at least one daughter Ann Robertson, born 24 June 1866. She married William Leiper and they had at least one child, Charles W., born circa June 1890. Ann died 7 July 1898 and Wm died 10 March 1909, age 43. He had married a second time to Mary Ann Malcolm, she died in 1909 age 31. They are buried in Dunnottar churchyard.
I have no clue what happened to the other siblings. I have found nothing in the OPR or census, and not even a marriage date for Charles Sr and Ann.
Can anybody help me find some answers? Does anyone know which Robertson septs were settled in Kincardineshire?
Thanks so much for your help!
Cheers,
Richard