Mabel, the birth record you found for William Henry Lloyd has to be the correct one, many thanks for that! Unmarried parents perhaps, as you say, though it still doesn't pin the connection between my Edwards family and William H Lloyd.
If Hannah Evans' maiden name was Pritchard, as suggested by the details you showed, then I'm back to square one on finding a link to Sarah Edwards. She's clearly stated as grandmother both in the 1871, and in the 1881 censuses. Perhaps then, Daniel Evans was not, after all that same Daniel as shown in the 1871, in Cefn, son of Godfrey and Anne, or, perhaps the censuses just got the connections mixed up? I'm a little confused by all of this!
I believe Sarah Edwards was born Sarah Clarke (marriage to Edward Edwards 27th Dec 1824, Ruabon).