As awesome as they would be, I am not expecting custom call-outs from Hanks or Allen.
I'd be good with mostly movie clips, they have a lot of material to work with there. Then supplement with somebody like Ratzenberger or Tom Hanks' brother.
Overall I'm not worried about call-outs or limited assets/IP. At the TPF seminar, Jack cited "full assets" as being one of the most important components of deciding what titles to create. They're not going to make games that they can't do "the right way." To me, that bodes very well for Toy Story.