Hi
in the 1881 census for Scotland there is the following family at 2 Ingleston St, Greenock East, Renfrewshire
John Ferris 22 born Ireland
Jane Ferris 20 born Ireland (wife)
James Ferris 2 born Greenock (son)
William Ferris age 6 months born Greenock (son)
Annie Rodger 17 born Ireland (sister in law)
This sounds like your family except for Jane. Could Jane be Elizabeth? or could Elizabeth be a second wife?
Andy