Hi Kim, I can't help you much with their parents but in case you don't have it already here's their household return for the 1841 Scottish Census...
MCLEAN, David M 55 1786 H L W Cotton Dumfriesshire
MCLEAN, Jannet F 57 1784 Dumfriesshire
MCLEAN, Agness F 20 1821 Dumfriesshire
MCLEAN, Thomas M 20 1821 H L W Cotton Dumfriesshire
MCLEAN, David M 1 1840 Dumfriesshire
KENNEDY, Mary Ann F 14 1827 F S Dumfriesshire
Piece: 817 Book/Folio: 2 Page: 11 Civil Parish: Cummertrees
Address: Powfoot, Powfoot, Cummertrees County: Dumfriesshire
...and their son Edward's...
MCLEAN, Edward M 35 1806 H L W Cotton Dumfriesshire
MCLEAN, Margaret F 38 1803 Dumfriesshire
MCLEAN, Margaret F 12 1829 Dumfriesshire
MCLEAN, Janet F 10 1831 Dumfriesshire
MCLEAN, John M 8 1833 Dumfriesshire
MCLEAN, David M 6 1835 Dumfriesshire
MCLEAN, Thomas M 4 1837 Dumfriesshire
Piece: 817 Book/Folio: 5 Page: 3 Civil Parish: Cummertrees
Address: Norwood, Norwood, Cummertrees County: Dumfriesshire
County Dumfriesshire
Place Tundergarth
Church Parish Church
RegisterNumber 93
DateOfBirth
BaptismDate 18 Aug 1793
Forename Janet
Sex F
FatherForename William
MotherForename
FatherSurname SMITH
MotherSurname
Abode Linhead
FatherOccupation
Notes abode pos. Linhall
FileNumber 3440