Continuing the bizarreness of this family, and bearing in mind the former surname McFarlane given when Susan died, how about this:
In 1881 a Susan McFarlane, 25, born Edinburgh is living with her husband Myles McFarlane in Edinburgh (not at address mentioned previously though). They have no children.
I looked for a marriage for them and could only find this:
Miles McFarlane 19, Carter, married Susan Crew, 18, Paper Stainer on 31/12/1872 (last day of year and comes up as 1873 on SP marriage index) at Port Dundas Church, Glasgow. She is shown as the daughter of a Henry Crew, Private 92nd Foot and Isabella Crew, formerly Johnston .
I'm wondering whether Stewart Ogilvie died very soon after the 1851 census and that his widow Isabella then had daughter Susan ca.1853 by the soldier Henry Crew. (Can find no marriage between a Henry Crew and Isabella Johnston).
In 1861 Isabella Ogilvie is with 4 children, one being Susan. In 1871 we now know Isabella was in prison and this could have prompted the move to Glasgow for Susan. When she marries Miles McFarlane she does so in the name of her natural father and as if her parents were married.
Sometime between 1881 and 1891 the couple split - Miles is still in Glasgow in 1891 but claiming to be unmarried. Can't find Susan anywhere. She then decides to marry William Spencer in 1897 and also claims to be unmarried using the name Ogilvie which she'd grown up with, and this time citing her father as Stewart Ogilvie, Isabella's dead husband.
Perhaps these events are all 'red herrings' but a 'Henry' (albeit given as Ogilvie) is shown as her father when she died, plus indicates she was previously married to a McFarlane.
It's been mentioned that Susan had no children and interesting to note that Miles McFarlane and wife Susan had been married 8 years in 1881 and they had no children!
Thought I'd run this by you anyway.
Annette