Luna and our cat, Gracie have been around each other for just over a year and they're finally getting used to each other. It takes time and practice.
Does your cat have claws? It's very helpful for the puppies when the cats have claws. Our poor Grace is clawless, so we really had to work on the leave it. But if it's too much, Grace will hiss, swat and bite. And then I see them snuggling on the Dropcam when we're not home ;-)