Yeah, the Chop Suey part seems to have been altered a bit. Slowed down a little in some parts and tone changed in other parts to match the key Crocodile Rock is in.
This is true. They did a pretty good job with the make up, and it's pretty close! I thought the movie versions looked slightly older than the actors themselves, but we still have 2 more years to go!
http://www.youtube.com/watch?v=drQVRaqPSuk