Bunnies laying down to pancake are a great sign, it means they are comfortable.
Rabbits do need enrichment items (toys), but not all rabbits like the same toys. My former rabbit loved flig toys-things like baby toy keys that he could throw with his mouth. My current rabbit doesn't really like those and prefers chew toys such as willow balls and loves running around her tunel.
Here is a great resource on how to win over a shy rabbit if that is something you are still concerned about. http://www.bio.miami.edu/hare/shybun.html