i want a westie too and i did some reserch and i know if you get a puppy and you train him do be good with the cat inside he would be good, but if you put them both outside together a dog is a dog and he would probally chase the kitty outside because thats a dog thing. i know when i got my flat-coat she was smaller then my kitty and she never chased them because she grew up having them around.

about potty training, almost any dog could be potty trained unless the had uti i think thats what its callled