Hi Kay, when we were introducing Malone & Marigold, I first introduced them where Marigold had a place that she could go that Malone could not. (For example onto the kitchen table) I let Marigold "swat" Malone on the nose when he got too nosy, and that put Malone in his place from the start. I also did this when we got Emerson.

I know your situation is a little different in that Simba is already situated and the cats are the newcomers.

My only suggestion is to relax a little and let them come to terms. Watch closely though! If Simba is just sniffing, the kitty probably will be fine with that. If he gets too nosy, she will swat. The case where you would want to intervene is when Simba started to growl or look as if he were ready to lunge or something.

Hope that helps, and the best of luck to you! I know that if ANYBODY could make a dog and cat get along, it would be you.