Is this the entry you found for Elizabeth?
1871 census, reference RG10, Piece 3100, Folio 6, Page 12
116 Bath Row, St Thomas, Birmingham
de Vere, Albert Head M 28 Army (Austrian) b Paris
de Vere, Ada Wife F 22 b London
Harwood, Charles Boarder M 26 Late in Army b India
Caswella, Lucy Boarder F 31 b Havant, Hants
Ryland, Emma Boarder F 51 b London
War, ELizabeth Visitor F 18 b Birmingham
Thinking about the family logically(?!):
Eliza emigrated in 1889, at the age of 29.
Did she travel alone? Or with elder sister Elizabeth and/or brother George Henry?
Elizabeth may have married - but so far I can't find a suitable marriage!
By the 1881 census she would have been 28 years old.
Of course, the other reason Elizabeth and George Henry can't be found is that maybe they died?