Goodness me, this thread is absolutely compelling, like reading a novel, but I'm so sorry that you're experiencing all this hassle. I had one incredibly easy bond with a baby male and a diva like 2 year old female. He completely won her over and even his neutering didn't break their bond.
I also gave up on a different bond after a ferocious locked on fight because I was so worried about abscesses forming from bite wounds. (I had another bunny who died because of one). I just gave up and they lived out their lives separately.
So I admire you for persevering. They are both stunning bunnies. I love Dilly's ears and Susan's snow white fur and gentle face.