No problem but there is still a problem with your definition of events - the Isabella Beveridge you linked to is not identified as having a husband called Alexander Oliphant or any son AND she was only born in 1874 so wouldn't have been allowed to be the informant at a death in 1883 at age 9 !
Nevermind - Anyway, to confirm Robert Oliphant was born in 1815 and was the son of Alexander Oliphant and Isabella Beveridge. Robert's mother was the informant at Robert's death registration, so she died later than 1883, so lived to be more than 82 years old. If any of this is misconstrued say so.
Are you sure the death informant wasn't a sister who was named after their mother? If this Isabella (the informant) is really your 3xgrtGrandmother she would need to be born approx 100 years before you (25 years per generation), so is quite unlikely to be Robert Oliphant's mother!
As long as my analysis above is correct, the parents seem to be in Fife in the 1841 Census...
OLIPHANT, Alexr M 55 1786 Watchmaker Fife
OLIPHANT, Isabella F 50 1791 Fife
OLIPHANT, Elisabeth F 24 1817 Fife
OLIPHANT, William M 20 1821 Flesher J Fife
OLIPHANT, Isabella F 4 1837 Fife
Piece: 402 Book/Folio: 1 Page: 10 Civil Parish: Anstruther
Address: Castle Street, Anstruther County: Fife
This census makes me think that the daughter born in 1837 might have been the informant at Robert's death registration? In any event Robert appears in some of the censuses (see below)...
Scottish Census of 1851...
OLIPHANT, Robert Head Married M 39 1812 Ag Lab Colipie, Fifeshire
OLIPHANT, Helen Wife Married F 34 1817 Cameron, Fifeshire
OLIPHANT, Margaret Daughter Unmarried F 13 1838 Flax Spinner St Andrews, Fifeshire
OLIPHANT, Isabella Daughter F 10 1841 Scholar N K, Fifeshire
OLIPHANT, Elizabeth Daughter F 8 1843 Scholar Denbog, Fifeshire
OLIPHANT, Alexander Son M 5 1846 Scholar Markinch, Fifeshire
OLIPHANT, Helen Daughter F 3 1848 Scholar Markinch, Fifeshire
Piece: 444 Folio: 56 Page: 24 Registration District: Prinlaws
Civil Parish: Leslie (Fife) Address: Prinlaws, Prinlaws, Leslie (Fife) County: Fife
Any more records I find I will add as comments...