My PENTLAND ancestors were tenant farmers at both Sunnyside Mains and Little France for many years. Below are some misc-refs in my files which probably relate to your family.
I cannot vouch for their accuracy, but I suspect your Marion Armour is Marion Armour b 9-2-1808 Liberton to James Armour & Mary Bishop. The family is in the IGI. Hopefully when you checked it out, all will become clear.
As far as I can see there is no familial connection with my PENTLANDs although George KNIGHT (my 5x-gtgdfather) is recorded as a Publican in the parish of Liberton in 1787 and his gdson, also George KNIGHT, was a publican at Little France in 1841; another relly, Andrew GRAY, was publican at Kirklands Liberton in 1828. So while I have recorded association between them and your James ARMOUR, they all must have known each other's families.
ISABELLA ARMOUR Birth: 24 JUN 1810 Gilmerton, Liberton, Midlothian Parents: JAMES ARMOUR MARY BISHOP
James Innes Birth: ABT 1810 in Midlothian?
Isabella Armour b: ABT 24 JUN 1810 in Gilmerton, Liberton
Dates above are palpable nonsense,.
Married: 10 MAR 1826 in Sunnyside Mains, Liberton
Children
Mary Bishop Innes b: 23 NOV 1826 in Sunnyside Mains, Liberton, Midlothian
John Innes b: 28 JUL 1828 in Craigs, Liberton, Midlothian
James Innes b: 30 JUL 1830 in Little France, Liberton, Midlothian
Helen Armour Innes b: 20 DEC 1832 in Little France, Liberton, Midlothian
Isabella Innes b: 22 FEB 1835 in Little France, Liberton, Midlothian
Anne Innes b: 10 MAR 1837 in Bridgend, Liberton, Midlothian
Thomas Innes b: 14 APR 1839 in Bridgend, Liberton, Midlothian
Sarah Innes b: 14 MAY 1841 in Bridgend, Liberton, Midlothian
David Innes b: 28 JUL 1843 in Bridgend, Liberton
Robert Innes b: ABT 1848 in Liberton
Willaim Innes b: ABT 1850 in Liberton
Isabella Innes b: ABT 1852 in Liberton
Alexander Innes b: ABT 1854 in Liberton
Also: "Hood : Mary Daughter to David Hood and Jane Steele at Carthall was born 21st Septr and baptized 12th Octr 1823 Witnesses James Armour and David Pentland" - Liberton OPR 1823.
"Balks : Andrew : Andrew Balks and Violet Armour : Gilmerton : 30-10-1810 : 10-12-1810 : Andrew Grubb and Wm Pentland.". Included here by virtue of the Armour surname, the place, and the eternal recurrence of William as a witness.
"So far as I can see Andrew Balks and Violet Armour had only two children; Helen in 1805 and Andrew in 1810 and the only Violet Armour which that could have been was the wife of James Armour with who she had four children between 1794 and 1800 so this suggests she remarried. The witness Wm Pentland is most likely to be the husband of Alison Armour, from the other Armour family. I have always believed Violet and James Amour to be related although naming patterns don't suggest they were cousins."