Going in February with some friends who have been umpteen times...but they have two girls. We have twin boys who will be 4 at the time. Our friends will have most things covered, but are there Any can't miss things for boys?
How tall are the boys expected to be in February? Have they shown thrill-seeking tendencies?
The answers to those questions will help figure out what rides they can/should hit.
Are the boys into any TV shows or movies owned by Disney properties? Classic Disney characters, Disney Channel, Pixar, Star Wars, Muppets, Indiana Jones.
A family with girls there to see the Princesses and Pixar might not give Animal Kingdom much consideration, but the safari and dinosaur stuff might be a big hit for the boys. The "it's Tough To Be A Bug" show at AK is fun and difficult to reproduce at other amusement parks. And if the boys like The Lion King even a little bit, the "Festival Of The Lion King" show is paced well and kid-friendly.
You're going in February. The good news is that's a relatively slow period for the parks so the lines won't be too bad. The bad news is it's also in the heart of the maintenance schedule, so some rides and such will be shut down.
Also to keep in mind... Your friends' girls will probably want to meet Anna and Elsa from "Frozen", and the wait for that could take hours. So plan on alternatives for your boys, unless they also want to wait hours to meet the Frozen girls.