As far as I can see from the parish records this is the way the Ennis family developed in Jersey
The first Ennis here was James (sometimes Jacques in the records), there is a record of James Ennis of Plymouth marrying Susanne Vautier of Grouville, Jersey, 26/11/1780. I think Susanne died, although I've not found a burial record yet, the next marriage is of James Ennis (Innes) from England to Elizabeth L'Her, this was 5/2/1786. I really need to find Susanne's death record to confirm that there is only one James.
James and Elizabeth had the following children,
Eliza Ann 1786
James 1787 - married Elizabeth Le Ray, children James 1813, Ann 1815, Jane 1818, James 1819, Elizabeth 1821-1824, George 1826 and Elizabeth 1829
George 1789 - married 1) Ann (Nancy) Sarre, daughter of Josué Sarre and Elizabeth Jeune, died 1839. They had children George 1813, James 1815, Nancy 1816, Elkizabeth 1821, Abraham 1822, Charles 1824, Josué 1825, Jean 1826 and Pierre 1828.
Married 2) Ann Stratton - baptism 21/10/1818 daughter of Samuel William Stratton and Mary his wife - their children you already have from the census returns
Ann Sara 1793
Abraham 1795 - married Ann (Nancy) Lomas, children Ann 1819, Eliza 1820, Abraham 1824-1824, Abraham 1825, George 1827.
Obviously there are a lot of gaps that still need to be filled, notably the dates of George's 2 marriages. You can see from the repeated use of Christian names that the Ennises will take a bit of untangling.
I'll try and find some more next time I'm at the Archive.