Hi
I checked the 1891 census and found the Langstaffe family at 4 Court, Beaufort Street, 2 House, Toxteth Par, Liverpool. All except William sen. born Liverpool.
William,32,Dock Lab.,Born Scotland
Mary A.,22,
Thomas,8,Scholar
Alice,5
William,10m
I immediately suspected that your Alicia Alice had died at, or soon after, the birth of 5 yo Alice and that William had remarried Mary A.
When I checked for the death on FreeBMD I found:
Alice Langstaffe, Dec Qutr 1866, Ref. 8b, 128.
Hope this helps
Marie.