We did actual beak tests, tests of talking dinosaurs that had the real beaks, and it came off as comic. It would have been okay for a sidekick character like Eema, but not for a hero character. However, in talking to one expert, there was evidence on some beaks of having small perforations on top edge of the beak. This might have been a blood supply for lips. Of course it is a difficult paleontological question.
Soft tissue disappears over time.
There are a number of things that are difficult in the film ranging from animation issues to lighting and composition issues. Each department had its own problems. Lighting compositing was very difficult. Lighting would change on the filmed background plates over the course of the day. Ultimately everything begins with pencil on paper here at Disney.