I'm not too sure but...
Basically before Henry VIII broke away from the Church, witchcraft was considered an act against the Church only. However, when Henry VIII did actually break away from the Catholic Church, it was deemed an act against the state & King. As it's against the king, it is treasonous therefore a capital offence.
Hope that helped but I'm not 100% sure on that...about 90% though lol :)
No. It is not a crime.
The name of the school in the series is 'Hogwarts School of Witchcraft and Wizardry'. Reading the books is not witchcraft, but it is a large part of the plot.
because men were considered to do wizardy and sorcery, not witchcraft.
No, Just a online threat.
Worshiping Nyx is not considered Witchcraft alone. You are simply worshiping Nyx. If you wish to practice witchcraft research it before aligning yourself with any deities (i.e. Gods/Goddesses). Witchcraft is not particularly a religion and therefore the worship of Gods and Goddesses is not a rule/must, but many Witches do honor their deities.
death
fire
The character Harry Potter is stupid LOL.
Intent and Capability
Violence or the threat (verbal threat) of violence is considered assault in the United States. The threat of violence is a crime and can result in jail time.
no
Yes.