Hi and welcome to the forum!
The money on her books will follow her, but sometimes takes a while to catch up. Up to a couple of weeks. It's a good idea to put a small amount on her books right away to ensure that she can go to commissary till her other funds catch up. It can take up to a month to get the phone list approved. Sometimes, even longer. As long as you have the account set up with Consolidated, when her list is approved and she gets her PIN, she'll be able to call you. The mail you've sent will catch up to her. Again, it will take a little while, but she should receive it. You'll also have to wait to have her visitation list approved.
Generic visitation rules - you'll need two forms of ID, one must be a photo ID. Dress like you're going to church. When you get to the facility, you'll have to fill out some paperwork. It seems very threatening the first time you visit, but you get used to it.
Other members may be more familiar with Decatur, I'm sure they'll be along to give you more exact information.
Again, welcome and always feel free to ask any questions you may have.