There are no relationship indicators on the 1841 census so Avarina could be staying with other family.
Yes, this is a possible line of enquiry, or as Carole has said, if mine is the Avarina in Middlesex working as a servant (where two years later she marries, so seems more likely), then this Avarina with Mary and others could be a relation - I'll try to follow that trail.
You need to check the baptisms for children of David and Ann(e) at Llanfihangel Y Creuddyn around the same time as that of Avarina and try to locate them as well as David & Anne in 1841.
Ok, so I found a baptism for children of David and Anne Hopkins, Llanfihangel y Creuddyn:
David 1810
Avarina 1812 (believed to be my ancestor)
Anne Hopkins 1815
Elizabeth 1817
Morgan 1820 (also a burial in 1820

)
Jane 1821
Mary 1823
John 1832
No baptism, but a burial record for a
Margaret Hopkins in 1842, age 16, in Llanfihangel y Creuddyn
No baptism for
Sarah either, but a marriage record to John Loyd in 1848.
I had found a David & Anne in 1841 and their children Mary, Margaret, Sarah and John (Carole also posted this).
There is a possible burial for Anne in 1844 so David is likely to be showing as widowed in 1851.
David is then shown in 1851 as widowed, with young John, and a John and Sarah Loyd with a child, and an Ann Chandler and 4 children (I have found a marriage between an Ann Hopkins and Richard Chandler in 1839).
Sarah and John Loyd are still with David in 1861, with 5 extra children, so I feel they must all be connected with the David and Ann from 1841, the David Hopkins and Anne Jones from Mary's baptism in 1826 John's baptism in 1832...
Is all of the above quite enough to connect Avarina with that David and Ann(e) family?