1) There is no way that the girlfriend of the thief (I can't even remember the characters', they were so dull) would be escape scott free. There is no way. Hawaiian surfer dude will eventually give her up. And it was her idea. She should go to jail.
2) Why could Jake Lacy's character just leave the island after STABBING a man to death the day before. Bullshit. They would keep him a little while longer to check his alibi.
3) I don't even care about the 16 year old son of the family who decided to stay on the island. Mike White, this was not some great statement that you felt you had to make. In the real world, he will become a teenage prostitute to fuel his idiotic need to be on a canoeing team.