The 1881 census records William and Jane Carnegie in Settlingwynd, Cortachy. William's birthplace is given as Edzell and Jane's as Forteviot (a few miles south-west of Perth). With them are William, 12; Ann M, 11; Susan I, 8; Jane C, 6; Mary,3 and Euphemia, 1, all born Cortachy.
The 1841 records William and Susan Carnegie in Invereskandy, Edzell. William born outside Angus, Susan and David, 10; John, 8; Isabella, 3 and William, 1 all born in Angus. This William presumably died young because there is an 'extracted' listing of William Carnegie, born 18 May 1842 in Edzell.
It seems quite likely that William and Susan survived until the start of civil registration in 1855, and if so there should be death certificates at
www.scotlandspeople.gov.uk which should tell you the names of both their parents. Go for Susan first because she will be indexed under both her maiden and her married names.
You will find out much more BTW if you arrange to spend a day in the Scotland's People Centre in Edinburgh before you travel to Cortachy, or Edzell, or Fettercairn, or anywhere else, because all the basic records you will want to look at are kept there, not in the individual parishes.
(PS and don't even think about trying to drive a car in Edinburgh. There's an excellent bus service and driving in the city is a nightmare surpassed only by trying to park in the city centre if you ever get there.)