The Osbornes typically run for an hour or so after park closing, so in theory there is time to do both. The tricky part is getting back deeper into the park after Fantasmic is over to see the Osbornes. CMs generally nudge you to the exits after park close. I *think* they are more accommodating in this particular case but I'm not sure I'd rely on that. As the PP mentioned, there is also the possibility that park hours will be extended, solving your problem for you.