Shelly,
You are going to have a great trip, I am sure!
Here is where I would go in your shoes;
- September 23 - Magic Kingdom
- September 24 - Animal Kingdom
- September 25 - Magic Kingdom
For a character meal, I would recommend getting a dinner in one of the resorts on the night of the 24th. Since the Animal Kingdom closes at 6 pm, you really need something to fill that time. Chef Mickey's is an obvious choice. If, however, you want to have one in a park, then get a breakfast reservation at Tusker House. Lunch would be good too, but avoid dinner.
If you go for the Tusker House idea, for that evening have plans to go somewhere else. If you want to stay on Disney property, I think Downtown Disney would be your best bet. Or better yet maybe a dinner at one of the resorts. 'Ohana or Whispering Canyon Cafe would be good fun recommendations.
For fireworks, definitely watch Wishes at the Magic Kingdom. On the 23rd and 25th they are at 9 pm and 8 pm, respectively.Write me back if you need other ideas!
Have a magical (and delicious) vacation!