I'm also of the opinion that Danielle will turn out to be Ronnie's daughter but, last night when Stacey was talking about Ronnie and Roxy Danielle didn't bat an eyelid - didn't seem interested which I thought was a bit odd.
She's obviously been adopted as she mentioned having a brother but has never given a reason for turning up in Walford. We really know virtually nothing about her still, except that she is a far more interesting character than soppy Callum!