Hmmmm... after getting 8 fur, there wasn't anymore M.Rabbit interactions... no option to kill the cats, and once it saves on 2.2 the save is white. So you really have to finish a normal playthrough before murdering everything? Or can I get back to it by starting to kill in 2.2 again?It doesn't matter how you interact with them, if you're going the genocide route you instantly kill them.
The mother rabbit interaction is after reading both the notes I think, it happens automatically at the end of the chapter if you read them. Not sure about the two missing fur though.