Probable birth for Marion.
Marion MACFIE, born 28 Oct 1818, South Leith, Midlothian, parents John MACFIE and Alison THORBURN.
John MACFIE marriage Allison THORBURN (father William THORBURN), 9 Nov 1810, South Leith, Midlothian
These parents had (at least) in South Leith (
extracted entries - there are also some LDS submissions):
*Robina MACFIE b 20 Sep 1814
*Mary MACFIE b 15 Nov 1816
*Marion MACFIE b 28 Oct 1818
*John MACFIE bap 18 Jun 1820
*William MACFIE bap 26 Apr 1822
*Ann MACFIE bap 20 Jul 1830
*ELLISON_MACFIE bap 11 Dec 1828, mother's name listed as ELLISON_THORBURN
Probable birth for Alison (THORBURN) MACFIE:
Allison THORBURN, bap 30 Jun 1791, South Leith, parents William THORBURN & Robinna SCOTT
There's also an Ann THORBURN to the same parents 1786.
JAP
PS: Perhaps you already know all of the above

I note the following website with
extensive information about the MACFIE family and with information about Maurice John LOTHIAN and also about Marion's second husband John MCEWEN:
http://freepages.genealogy.rootsweb.com/~macfie/john_of_leith.html