When Chester came home to live with us at 8 weeks old, we had three cats aged 7, 8 and 10. Our cats had never been exposed to a dog before, so we were not sure exactly what to do.
Our vet recommended that we made sure the cats were able to get into an area or room that Chester was not allow in. So we did that. We also bought the cats out to meet chester one at a time. Our male Nigel being the oldest was not impressed with the new household addition. We introduced them and after the hissing and spitting stopped, they seemed to be able to tolerate each other. They still got into spats but they were just small, no blood. We feel that Chester understood that Nigel was the dominate male and he ruled the house.
With the girls, totally different, Matilda hide from everyone for weeks, only coming out to see us if she knew that Chester was not even in the house. and Gabie she would just smack chester on the nose. He learned really quickly that when she hissed, it meant stay away.
When Nigel just recently passed away, we were worried that Chester would see this as his right to be top dog, but it hasn't. He still knows that he is lower than the cats on the household scale.
Just be sure that your cats have an area that is completely dog free, teach Moab "leave it" , which works great for other things too and that you don't favour one over the other. Hopefully, your cats will accept Moab, and he will understand that they aren't big furry squeak toys and everything will work out for all of you.
Chester - born Nov 3/03 - Fawn, Docked and Floppy
Lilly - Born March 7/07 - White, Docked, Floppy & Deaf