Disney only owns the rights to their movie and the charater designs they created for it. The actual stories and the "basic" characters are owned by the children's hospital - and they are free to license them to whomever they wish.
There will be another moive later this year about the life of JM Barie starring Johnny "Pirates of the Caribbean" Depp that will also cover the 'Peter Pan' story.
There are rumors that the hospital, that relays on the royalties for a substantial amount of its funding, that they are displeased with the way Disney has be handling the licensing lately. And they been paying very close attention to the ongoing lawsuit over the royalty payments that Disney owes on 'Winnie the Pooh'. It's said the 'Peter Pan' rights holders are looking for other people to take over all things 'Pan'.