I currently have 2 unneutered male cats of unknown age. I suspect one is 1-1.5 and the other seems much older for his size. I have had them for a month, and the younger cat only went outside of the box twice, both times I believe because he smelt dogs on some stuff I have. It wasn't like he sprayed, he just took care of #1 on the floor near these items. Now, I've had this cat that has started coming around my house and I have paid no attention to him short of giving him a bowl of water and talking to him while I work outside. Regardless, he has taken to sitting by my back door crying day and night, waiting for me to come outside. From what I can tell it is an older, reasonably well-fed, declawed, and neutered male.
It is my understanding males will mark their territory when they are around other males and a female, but if I were to add this cat to the family it'd be 3 males in the house, what's my chance of my cats marking territory against this new guy? Does the fact that mine are unneutered and he is neutered have any correlation? Honestly I'd prefer this new cat over my younger one but he is very close to my other cat and they have already clearly established I'm their owner so I'd hate to break that up.