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 fling toys--things like baby toy keys that he could throw with his mouth. My current rabbit doesn't really like those; she prefers chew toys such as willow balls and loves running around her tunnel. 

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