Actually yes all... Disney covers the overhead costs of the fund. That's one of the reasons why it's actually a really helpful organization, because everything donated actually goes towards helping the animals and not towards paying people, accounting, etc...Not "all" - "proceeds" People gotta be paid, trucks maintained and fueled etc. Not sure if a cut off the top goes to the general operation of the park.
Each donation is matched by Disney and this is not charitable so no reporting. They granted $40 million over the last 22 years from this fund. Less than the take for one day's admission to one park.