In the cannon world, Chapter Six (the train) is 25 pages and Chapter Seven (the sorting and feast) is another 18. A lot of critical stuff happens in these chapters, some of which I have to change. For now assume this is just Chapter Six. How does Harry find the platform? He needs to end up in a compartment with Susan & Hannah, not Ron. Can children see him, or is he only functionally invisible to adults? Has this gradually changed due to continued Legilimency? I think this last, they cannot see him. Decide on uniforms, this has a lot of implications.