Honestly, I don't have a problem with her getting a less aggressive bunny. If that is what she wants to do then that is fine. As long as she can properly care for the new bunny than that is what counts. Maybe she can check up on Roxy to see how everyone is going with her every once in awhile. I'm sure the shelter will do what is best for Roxy as well. From what I read Buttercup cared deeply for Roxy, but when an animal gets too agressive then you have to go with your inner feeling and do whats best for you and your animal.