Sounds pretty good! I know not having caffeine is the pits for someone who is used to having it. But, unfortunately, caffeine will drain her of the liquids/minerals she needs. Maybe, she can find decaf coffees that she likes.
Flavored waters and juices are a great way to get fluids.
I have only been severely dehydrated once when I was in 4th grade. I never will forget that. I was so bad I was hallucinating. I try to not let it happen again.
Hope your daughter can adjust to her new diet soon. It's actually adopting a new lifestyle. Best wishes and prayers for her.