Hi Christina,
For the most part you can order any entree or dessert that is listed on the menu. At some restaurants there are menu items that are meant to serve 2. In that case, the menu will state that two dining credits are needed to order that item. Your server will ask if you are on the dining plan and point out any menu items that might fall under this category.
Looking at the Coral Reef menu, I don't see any items that you wouldn't be able to order.
There are some really fun restaurants, with great food, at Walt Disney World. Some of my favorites with kids are:
'Ohana, Whispering Canyon Cafe, 50s Prime Time Cafe, Via Napoli, Biergarten, Garden Grill
If you're looking for signature dining (2 credits):
Jiko, California Grill, Flying Fish Cafe
Every restaurant in Walt Disney World is great for
celebrating birthdays and special occasions. At most restaurants there are small cakes for purchase. You can also order something more personalized to be delivered to your table. Just call (407)827-2253 at least 48 hours in advance.
Hope this helps. Have a magical vacation!