Hi, Barbara!
Disney's Art of Animation is such a fun resort. So much Disney fun truly larger than life, with
something new around every corner. Make sure to plan to enjoy a few meals at the resort since the food court,
Landscape of Flavors, is out of this world.
All the rooms in the Little Mermaid section are standard rooms with 2 double beds. You are correct that there are king beds available, but these are considered "accessible rooms" with roll-in showers, no bathtub. Because there are so few rooms with king beds, and they are given with priority to guests with special requirements, you will only get one based on availability.
To increase your chances of getting a king bed, I would call (407)934-7639 and have your request noted on your reservation. You can ask again at check-in, but please know that they may not be able to accommodate your request, just based on the number available.
Wishing you a magical stay at Disney's Art of Animation!
Cathy