The sheriff finds Pete's car with the shotgun laying on the backseat. She doesn't charge him with a crime since he has a "license". No license or permit is required to own or transport a shotgun in Iowa. However, it is illegal to transport one without it being locked in a case or disassembled.
When the group is arguing after Luc stabs the girl who hates Catcher In the Rye, the victim is supposed to be dead with a knife in her back, slumped over the chair, but she can clearly be seen breathing.