Have you viewed all the baptisms of the children on Scotland's People? Because around the late 18th and early 19th century, the parish clerk in Rothes sometimes recorded the relationship of the witnesses to the child. Here are some examples:
"1776, January 16. James Leslie in Davie's Housie had a child in antenuptial fornication with Margaret Douglas now his spouse baptised and named Joseph. Witnesses Joseph Leslie in Davie's Housie, grandfather to the said child."
"1802, July 3. William Leslie farmer in Netherley and his spouse Jannet Inch had a child baptised and named John. Witnesses John Leslie the child's grandfather John Sim in the Hill and Ann Leslie the child's aunt."
"1808, 17 August. Robert Cruickshank mason in the Town and his spouse Ann Leslie had a child baptised and named Grizel. Witnesses Grizel Leslie the grandmother James Sutor Junior and Senior in the Collie."
"1810, 31 May. Robert Cruickshank mason in the Town and his spouse Ann Leslie had a child baptised and named Alexander. Witnesses Robert Leslie in the Folds, Alexander Cruickshank the child's grandfather and Alexander Sharp in the Town."