Elizabeth married Essex Griffiths at Malew on 15/04/1847. They had one son, as far as I know, also named Essex.
They cannot be found on the 1851 census or the 1861 census and no burial record on the Isle can be found.
So from this I would think they emigrated, probably to America, but until proof can be found, that is only speculation.
Mother, Elizabeth (Holmes) is on the 1861 living with her married daughter Hannah (Sayle) and John, her son, is also there. But the elusive Mary is not.
John married Eliza Mylechreest two days before his mothers funeral on 1/4/1863, although he had been married to Mary, he is described as 'Bachelor'.
These Victorian folk have a lot to answer for to the present day researchers. lol