Thank you for such a great question! Walt Disney World has many options for resorts that your family may like. Since you first mentioned a love of animals,
Disney's Animal Kingdom Lodge is amazing as there are rooms that overlook a savannah; imagine having giraffes and zebras right outside your balcony! It is also located a short distance from Disney's Animal Kingdom. Even if you don't stay at the resort, I'd encourage you to make reservations at one of its restaurants so your older daughter can enjoy the animals and resort.
Disney's Port Orleans - Riverside is a moderate resort that actually has Royal Guest Rooms where Princess Tiana and her friends have left little items behind. It is perfect for little princesses! As it is a moderate resort, it is not located directly near any of the theme parks, though.
Disney's Art of Animation Resort may be a good compromise for both of your daughters as it is a value resort with jaw-dropping theming from
The Lion King,
Finding Nemo,
Cars, and
The Little Mermaid (both animals and princesses!). The resort has family suites and standard rooms. However, it is also not located directly near any of the theme parks.
All the above resorts do offer complimentary transportation to the parks, which is quite simple but you may have some longer bus rides and waits. If you'd like something with the easiest transportation,
Disney's Polynesian Village is hands-down the simplest. You can take a boat or monorail to the Magic Kingdom, and you can take a short walk to catch a monorail that goes directly to Epcot. If we can help with more information, please let us know.