It's still too early to tell. Some cats accept others faster and then some will only tolerate the new cat. I'd take the introductions very slowly. You may want to get a towel and rub Lancelots scent on it so your other cats can get used to his smell. Then use a different towel and rub Tuckers and Claytons scent on that so Lancelot can get used to their scent. Hopefully in time everyone will accept each other. Good luck. I love the name Lancelot and wouldn't change it if I was you.