The crinkle can be achieved with the plastic bags from some type of tortilla chips. Be sure to wash the salt and oil off before using.

There are some types of small flat plastic squeakers, available. Check online at craft supply stores like CR Crafts. Small flat digital sould boxes are available if you don't find them too annoying. There are even some that you can record your own sounds such as your voice or music, laughter, etc.
Anything that you use should be anchored securely inside the pages so that it may not be accessed by the child. Be sure to sew the plastic crinkle sheet into the seam allowances inside the page. The squeaker should be encased in a small fabric bag and then sewn into the inside of the page before you turn it inside out. HTH!