Diedeirick Santer killed Danielle, which was years ago...time to get over it love.
Anyway, I think the OP has a point.
Courtney Mitchell would be a great addition to the Mitchells. Her backstory is steeped in one of the most iconic soap couples of the 90s in Grant and Tiffany. I think it said a lot that they managed to find great female partners for Grant after Sharon, like Tiffany, Lorraine, Louise Raymond, Kathy and always brilliant with mum Peggy.
Courtney I'm sure wouldn't be a huge fan of Sharon, given what her Nan has no doubt told her about her. I can just picture Peggy sitting there, drink in hand on Sharon and Phil's wedding day, regaling Courtney with the tawdry details of "what that Sharon did" to her boys. And probably manage to convince Courtney, that if Sharon hadn't messed her father's head up the way she did, he would have been nicer to her mum and maybe things might have been better.
I think I'd like to see Courtney, before we see Louise. I don't think Louise would voluntarily come back to Walford after the nightmare her father became the last time she stayed with him.