Hi Kasden.
I've had a quick look and haven't had any success finding Robert Findlay (he's hiding well).
Three suggestions-
Firstly - Have you looked for an approx. 3/4 year old Robert Findlay (and variant spellings) on Scottish 1851 Census.
Secondly - Could be that Robert was illegitimate and was under the name Hails/Hales/Hailes (lots of variations with this name too
)
Thirdly- Can the names of Robert's children offer any clues? Grandparents/family names were, as you will probably be aware, passed down.
Hales was not that common a surname. I did find this -
https://familysearch.org/pal:/MM9.1.1/XTVT-H58Jane Hailes marries a Hugh Martin 16th Nov 1850 at Liff Benvie and Invergowrie, Angus
This couple according to Familysearch have 7 children between the years of 1857 -1872 at Dundee.Angus , but I suspect there may be more. Probably births pre- Statutory Registration in 1855 for which no record exists now?
Of course this may not be Jane Hailes mother of Robert Findlay but it might be worth finding this family on the 1851 and 1861 Census to see who's all there.
Looking for a Jane Hailes in the right area turned up this girl in 1841
Jean Hails age 11 born in Angus. see family below
Todsburn Lane Dundee.
James Hails 50 Mason Journeyman
Isabel Hails 20
James Hails 14 Turner Apprentice
Jean Hails 11
Jean Gray 50
James Hearn 55 Labourer
All born Angus except James Hearn (born outside county/he's probably lodging with family)
Jean Gray is James Hails wife.
Jane/Jean interchangable names.
Again, this may not be your Robert's mother. But she was the only Jane/Jean Hails of a suitable age that I could find.
Hope all this helps your search.
Good luck
Looby