Copyright ....

Hello, I have a few questions and I would be so happy if you could answer them! 1. I want to make video that is about e.g cheapest cars in world, is it copyrighted if I put same cars in video as another persons video? 2. Am I breaking the law if I dont put all cars that are cheapest (like spreading false information)? 3. Can I use wikipedia pictures, am I going to get copyrighted? 4. Can I use few seconds of someones youtube video in my video? I will have voiceover and I will credit them in description.I know some of these questions are stupid, but I'd rather ask than have something bad later