The constant bird sound heard is a native Australian Kookaburra.
The snake that comes out of the skull (at least apparently) is referred to as a "Boa," when it is actually a Ball Python.
When the snake is coming out of the skull it is very obvious it was coming out from below the table.
When they are trying to get into a locked room, Jessica takes a paper doily off the table and slides it under the door, then uses something to push the key out of the keyhole out of the lock to fall onto the paper. However, she put the paper under the middle of the door, NOT under the side of the door where the keyhole is, so the key should have fallen onto the floor, not onto the paper.