We have a 6 month old Hav, and I have 2 ragdoll cats. The cats are 6 and 9. It is not an easy process and it will take time to get them adjusted. The cats hid from the dog for a few weeks. One of the cats hid in his carrier everyday and I used to tell him that I was sorry, but no one was going to come and get him out of here. It continues to get better between them all every day. Just be patient and give it some time. I still keep Brady (the Hav) in the den and kitchen area with us, and the cats have run of the house. They can jump over the gates and get away from him, and they have learned that they can jump on a kitchen chair to get away from him if he is getting too wild with them.
Patients is the word for sure!!! Yoda didnt like our cat at all or my mother n laws cat scared to death of them but a friend had a cat that I sat for , for about 2 weeks the first week was stay away LOL then second week was playing all the time.So it can happen that they can get along. Or not hate to say. Our cat happen to disappear one day so now we just have Yoda and a parrot yoda can careless about the bird and the bird feels the same way as yoda LOL Good luck on cat and dog issue !!!
I have 3 cats and my Hav became the boss of all of them. One cat is an indoor/outdoor cat, and when he wants to come in, Kodi barks to let me know. They play/fight all day, but we all sleep together at night. Just give them time and their own space, and it should work out just fine. I have always had cats and dogs living happily under one roof. When my older dog was alive, these cats used to sit on him and clean his ears.
I have a Havanese puppy (Sherman) and a kitten (Bella) who are the same age--6 months. The kitten gets along better with the dog than my 2 older cats who are disdainful of them both. Sherman chases them whenever he gets the chance. I moved the cat food and litter boxes upstairs and block it off so he can't get to them. So the cats mostly stay upstairs unless he's in his ex-pen. The only cat who is nice to the puppy is Bella. She's really attracted to him and comes back downstairs immediately after being chased away. I've heard him yelp when she manages to get him with one of her claws. I squirt him with a water bottle whenever I catch him chasing them, but he's so fast I hardly ever manage to get him. I don't think there's a magic solution to the problem except patience and time. I can envision a time when Sherman and Bella become friends, when he's older and not so crazy. They are both in the hospital tonight after he got neutered and she got spayed. It's incredibly quiet here!