I think since this was going to be your first foster you did the right thing. The lady should think the same if she knows anything about animals. She should be exceptionally happy that you're keeping your own animals in mind because that shows you ARE a dependable and responsible person.

Have a more calm dog would be a lot less hard on your animals until they get used to having guests often. You've got to go with your gut instinct and do what's best for you and your animals.