Only two; Colin Creevey and Vincent Crabbe. Most students were evacuated. The only students allowed to stay had to be seventeen although some did sneak back in. It is possible that some of the fifty unnamed were students.
Towards the end, it centers on Hogwarts for The Battle of Hogwarts.
Damaged, not destroyed.
Likely Hogwarts.
At Hogwarts
In Harry Potter And The Deathly Hallows Harry gos back to Hogwarts in the 29th chapter.
yes harry potter goes back to Hogwarts
Severus Snape is the headmaster of Hogwarts in Harry Potter and the Deathly Hallows.
No, Fred was dead he couldn't return to Hogwarts.
It is not sure that winky died or not as there was no mention of her in the deathly hallows ,so we can assume that she survived in the battle of Hogwarts.
in the deathly hallows at the battle of hogwarts
Severus Snape
He becomes the Herbology teacher at Hogwarts.