Always opt for outdoor potty business if you can do this. But I would suggest leaving a wee wee pad down. I believe they are accident prone, lol
If you are getting a puppy it is crucial that your children learn to respect his/her size. Yorkies may be devils but they are extremely fragile. Please do not let the children try to teach her to jump off a chair or anything like that. Their little legs are tiny and damage can be done. Trust me, you don't want leg problems!
No need to be nervous. Remember,you will be her new Mommy, she needs to feel safe and secure. You don't want her to feel insecure. She/he may pick up your feelings. Maybe rather than nervous,you're more excited? lol
Dog food, you will have so many opinions. Not all opinions are wrong and not all are right.
Use this site in helping you decide your dog food. It tells you everything you need to know, plus their suggestions on all the dog foods listed.