You have to catch as many pixies as possible (up to 10) within 50 seconds.
Yes, Harry Potter and the Chamber of Secrets was released on Pottermore in 2012.
Chapter 5 of Harry Potter and the Chamber of Secrets was released on the 18th September 2012.
You don't interact with the diary in this chapter.
The hairpin is collected in chapter 4 of Harry Potter and the Chamber of Secrets in the moment titled "Lucius Malfoy". It can be found in the hair of the blonde girl.
Chapter 5-11 were released on the 18th September 2012.
You can find a guide on the Pottermore Wikia.
You have to click on the spells coming from the wands. They are identified by the colours.
It is open now, you should be able to access it so long as you have finished the previous chapters.
Chapters 5-11 of Harry Potter and the Chamber of Secrets was released on the 18th September 2012.
Harry Potter and the Chamber of Secrets wasn't released for a long time after the opening. You should now be able to access it after completing the first book.
Chapter 5 was locked for a long time as it had not been released. It should be open now, if you still can't access it make sure you have completed chapter 4.
Just keep your mouse over the glass and it will disappear. When it glows, it disappeared. Nothing really happens after that.