I've made a ton of these! The one suggestion I would make is instead of using batting use craft fuse. I like how stiff the pages are. Only fuse one side. To me it's so much easier for the young child to hold the book.
Be aware that not all the panels are printed where they'll line up. Also instead of cutting on the cutting line, move out 1/4 of an inch and then cut the panels out. that way you're actually sewing on the cutting line and you won't lose any of the book that way.
Good luck!