This suggests that the mother of John and George is Beatrix Charteris not Helen Chisolm?
"Henry, 12th Earl of Crawfurd, married (1) Beatrix, daughter and heiress of George Charteris of Kinfauns, and had issue — Sir John Lindsay of Kinfauns, and George, 13th Earl of Crawfurd ; (2) Elizabeth, daughter of Sir James Shaw of Sauchie, and had issue — Alexander, d.s.p., and Ludovick, 14th Earl of Crawfurd. (Douglas's Peerage of Scotland, Vol. I., p. 381.)" https://archive.org/details/anent1884/page/119/mode/1up