Fascinating. I quite enjoyed 'Trixie's visit to Andy. And she's a lion animagus? Wouldn't that just have thrilled her little Slytherin soul? Actually, she might have enjoyed the irony; who knows? I was wrong about her being the history teacher. Oh well. Choosing Surrey's zoo seems significant, but since she's after Neville I don't know if it is or not.
I'm glad Harry's going to become an animagus. A rhino is an interesting choice. I also liked that you made Liz's form a mouse. It could become quite useful if she chooses to pursue it. Look at Peter the rat.