In fact, he might even pursue his own rabbit-friend if they encountered each other outdoors. There are two lessons here. The first is to make sure you set up a situation where Felix is unlikely to feel predatory. The second is that even if Daphne has a feline friend, she could still be terrorized by an unfamiliar cat. Daphne takes charge, bossing Felix, chasing him and generally throwing her weight around.
Rabbits tend to be much more confrontational in social situations than are cats.
I believe this is because, at a very basic level, rabbits are group animals and cats are solitary. We need to figure out who's who in the social hierarchy. A large furry creature who isn't running away from me. Domestication has modified these instincts in the cat to the point that most domestic cats prefer to live with at least one feline companion. And of course there is a great deal of individual variation within species, from the human hermit to the gregarious cat.