Cats are very easy to take care of because they will be SURE to tell you if you do anything wrong

I think its a great idea to get a cat, and an even better idea to get TWO! Thanks for going to the shelter instead of a breeder

That surprises me they have so many outdoor cats there

Expect the kitties to be scared at first of the new environment and of the dog. But they will come around. Give them a place to hide (under a bed, a covered box, etc) and they will come out and explore as they start to feel comfortable. Be sure to put their food and water and litter box near where their hiding place is. But they also might not even need to hide!