I am convinced that Heather Sinclair was the child of Charlie from Charlie's Angels.....heard of but never seen.
As for the Spinner/Jimmy situation, here is my take: As soon as Spinner became involved with Satan, I mean Jay, we knew that something bad would happen. The bullying of Rick went entirely too far even though I understand why they were doing it. He did get off scott free from almost killing Terri. That said, it was still occurring on school property and nothing was done to stop it. Raditch did nothing when Rick came to him.
Not long before the shooting Jimmy and Rick were on positive speaking terms. They were getting along. At the shooting, imagine Jimmy's surprise when Rick confronted him. He was being accused of engineering the prank and had absolutely no clue why. Then Rick shot him. After the shooting, it would be logical to assume that Jimmy wondered why Rick turned on him. Only two people knew why Rick shot Jimmy..... Spinner and Jay.
During Jimmy's time in the hospital, Spinner couldn't even bring himself to go see him due to guilt. He knew that both he and Jay were responsible for the events that led up to the shooting. Unlike Jay, Spinner had a conscience, (although at times a very slow acting one) and he knew that telling the truth was the right thing to do. It was Spinner taking responsibility for the role he played in all of it plus giving Jimmy the answer of why Rick turned on him. It was a great moment of maturity and development of Spinner's character. The fallout was realistic and expected. A great job by all actors involved.
As for Liberty and JT. Liberty knew what she was up against with JT. He was a clowning, girl obsessed, pubescent boy. She knew he didn't have any real interest in her in years prior. She just couldn't help herself (I've been there) but to keep hoping that one day he would come around to her. It's true that he was rude to her at times. That said, she could be too with her perfectionism. It becomes more apparent leading up to their break-up. They should have ended up together. They were opposites that attracted and balanced each other. Unfortunately, we never got to find out what could have been.