Hello,
I am actually looking into this family as my great great grandmother was Margaret Moffat who was one of the daughters of Rebecca Stevenson and James Moffat.
Rebecca Stevenson's parents were Mary McClellan/McClellan and Hans/Hans Stevenson... he did go by Robert on census while living with daughter Rebecca and her husband James
Twist is Rebecca's birth certificate and her sister Janet both have fathers listed as Thomas Stevenson/Stevenson/Stephenson
Record details
Name Rebecka Stevenson
Gender Female
Age 0
Birth Date 23 Oct 1802
Baptism Date 14 Nov 1802
Baptism Place , Old Monkland, Lanark, Scotland
Residence Date 1802
Residence Place Old Monkland, Lanarkshire, Scotland
Father Thomas Stevenson
Mother Mary Mclalan
So she either had children with two brothers or he went by 3 different names... additionally Rebecca Stevensons death certificate lists her mother as Mary Mclaren, so someone mentioning those two names being often confused helps alot....tho will make my life a litte difficult lol because my great great grandfathers mother was also Mary Mclaren (nee Anderson).
Where I have become stuck is, my Great Great Grandmother Margret Moffat married Thomas Mclaren, who was a journeyman for a brass foundry. They supposedly were to have my Great Grandmother, Rebecca Mclaren... however I do not find any Rebecca Mclaren birth records she was supposed to be born Dec of 1854 per census records of USA, but I did come across Rebecca Moffat (Stevenson) son John Moffat living on Bedford Lane in Hutchesontown in 1861 with a Rebecca McClellan age 7 who would have been the same age as my great grandmother Rebecca Mclaren. Margret and Thomas would have been married then but Margaret is living with her mother Rebecca Moffat (Stevenson) and using her maiden name, which I think was not uncommon back then because her sister Janet is listed as Moffat as well but her husband Alexander Hogg is living there as well. There was also 3 little Mcphee children showing up randomly living with them but I have yet to find connection to that last name.
Robert Stevenson who married Margaret Armstrong was Rebecca Stevensons brother, however Rebecca also had a son Robert Moffat who married Catherine Kellachan and Susan Sellars. Hans Stevenson who married married Mary Aitken is yes also son of Hans and Mary.
The only marriage record for Hans marrying a Mary McClellan is 1827 and not sure about that, will dig into a potential marriage to a Mary Mclaren tho!