I feel like this question is a matter of opinion. Are there options? Or is this just open ended?
Here are a few names based on the descriptions:
Spot
Black Abyss
Splotch of White
If it were me I'd probably end up naming the rabbit something like Mr or Miss Fluffabundle and shorten it to Mr or Miss Fluff unless he/she was in trouble.
(Sidenote: Is this an actual school question or a personal one? Not being judgmental, I'm just curious.)
Hope this helps!
