A new kitten can be an impulse acquisition. It’s not the wisest way to make this decision, but I’ve been there. As long as you understand this is a fifteen to twenty year commitment and that unexpected things can happen, give homes to as many deserving kittens as you can!
But, the current rulers of the domain will need some time to adjust to their new roommate. Think of it like bringing home a new spouse after a few minutes of fun at the bar. Not always the best way to start off a relationship.
Give the kitten some space. A separate room with food, water, litter, resting place, hiding place and toys. When we brought Mojo into our home, he got the guest room at first. He was okay, he was used to close quarters at the clinic, but we had to make a special effort to spend some time with him.
What did my cats think? Ziggy was intrigued. A new resident, she could smell him. Also, she loves food and Mojo gets canned food. She was instantly interested.
Ruby? Well, not so much.
She headed for the hills and acted like the world was going to end every time she caught sight of her suave new roommate.