Just been wondering about the John, mentioned as putative father by the OP.
The family in 1861
Westwater, Langholm
ELLIOT
James, 57, farmer of 5576 acres, employing 5 shepherds 5 labourers, b. Castleton
Margaret T, w, 43, b. -do-
John, s, 12, b. -do-
William, s, 11, b. -do-
Thomas S, s, 10, b. -do-
James Thomson, serv, mar, 29, farm servant, b. -do-
Sarah Skellen, serv, unm, 30, dairymaid, b. Canonbie
Jane Warwick, serv, unm, 17, housemaid, b. -do-
John not found afterwards but SP have a death in 1866, Langholm, for John Elliot, aged 18, mother's maiden name Little.
So - that part of the story was wrong, it must have been Thomas S! I like to tie up all the ends

Wonder if this is Lillie:
https://familysearch.org/pal:/MM9.1.1/X729-DNMbrevitas