what did they do with Keiko's body?

Keiko was not just a whale. He was so much more than that. He showed that captive whales can learn to fend for themselves, even if he did return to human company. He learned to capture fish and interact with wild whales. Yes, it's true that Keiko wasn't the best rolemodel for releasing. They could've picked an orca that was captured at an older age, like 6 years old, when the whale would've been capturing fish for itself and not depending on his/her mother. Keiko was captured at two years old, he clinged to humans because he didn't have his mom and family.

What do you expect them to do? Put his dead body in the sea? They proved that their bodies will wash up eventually no matter how much you weight them down. Feed them to the dogs (literally)? You'll have the public all over the foundation because Keiko meant so much to them? So let's not say he's just a whale.