Other mistake: When Veronica and Lilly find the camera in Echoll's guest house they show it on the ceiling fan pointing down on the bed. When they view the tapes of Aaron and Lilly in bed the camera view is coming from the cabinet and not from above them.
Other mistake: Season 1, episode 19, Hot Dogs. After Veronica bugs the Spanish-speaking man who returned the dog in the park, a shot of her laptop is shown. It's the exact same shot as when Veronica was helping the valedictorian front-runner find out who was harassing her. There are books and even the girl she was helping in the shot, proving that the shot was not in Veronica's car, as seen in the very next subsequent shot.
Answer: 1. No, the pep squad uniform was green and yellow. 2. He failed one of the classes, the one where they were trying to launch an egg from various heights without cracking the egg. He was pairing with Angie Dahl, who told the teacher that he didn't do anything in the project. The teacher then asked him to pick the project he worked on, and he couldn't do it because he didn't help. Then the teacher told him, "See you in summer school." He couldn't graduate with everyone else because he needed to attend summer school in order to pass that class and graduate. It's assumed that he did, in fact, attend summer school, despite all the mess that happened in the season 2 finale.