How hard are these AP Classes? On a scale of 1-10 (1 being super easy to 10 being hard as crap)?

That depends you you. What kind of student you are. What classes you have already taken, what your grades are. And on the teacher. Not all AP World history classes are going to be taught the same,
My daughter took AP calculus , got an A+ in the class and a 5 on the AP exam with no problems. That doesn't mean it would be an easy class for you. She wouldn't of done that well in AP World History.

Go talk to the teachers who teach these AP classes in your school.

Lang and comp - 7
Psychology - 5
World history - 7
Environmental science - 6