Shedding, unfortunately, is something that we humans cannot do very much about. I think that the furminator is usually what is recommended as one of the best, so I’m not sure of anything better I can recommend.
As far as digging on the couch, I would recommend buying a cheap fleece blanket and putting it up on her favorite spot, that way she can still visit the couch with you, but she can dig at the fleece blanket instead of the couch!
The peeing on the couch could be from what Sarita mentioned, she may not have been able to get back to her box. Also, it could be her “marking” the couch. The couch and the bed are two of the MOST favorite places of bunnies to mark because they smell so strongly of us humans.
As far as the scratching, I think she is requesting pets from you
My bunnies also scratch at my knee to get pets from me, and I kind of like it because I feel like it is one of their ways of talking to me!