My view on this Edward chap is that a middle name of Douglas in conjunction with the At[t]well is virtually unique ....
But as to what his real relationship was to your lass, who knows, I've seen more 'fabricated' fathers on Marriage certs than .......

Again the Marriage Cert - is it the original, as signed by all parties, or a modern copy (which is in fact a copy of the Register entry, and hence has no original signatures ... )
He is at the 1891 census refn I gave, albeit transcribed Alwell ....