The headmaster or headmistress's name is unknown. All we know is that somebody new takes over and Professor McGongall retires.
It is unknown, we only know that it isn't Professor Minerva McGongall who retired.
constellations
I would say Harry's favorite place is Hogwarts because it was his first real home.
Hogwarts's (Hogwarts is Harry Potter's school) motto is "Draco Dormiens Nunquam Titillandus" which means "Never tickle a sleeping dragon".
Ginny Weasley.
The "school for magic" in Harry Potter is Hogwarts School of Witchcraft and Wizardry. There are four houses and each one bears the name of the four founders of Hogwarts, respectively: Gryffindor, Hufflepuff, Ravenclaw, and Slytherin.
Yes, along with Ron and Hermiones children, and Draco Malfoy's children.
constellations
I would say Harry's favorite place is Hogwarts because it was his first real home.
If you mean Hogwarts, no one know, except for the fact that it's in Europe.
That'd be awesome! I also think it would be amazing to read about the lives of Harry's parents, Sirius, Snape, and everyone during that time. :)
Severus Snape He had known Lily before they both went to Hogwarts
Hogwarts's (Hogwarts is Harry Potter's school) motto is "Draco Dormiens Nunquam Titillandus" which means "Never tickle a sleeping dragon".
The death of his parents, his entrance at Hogwarts and his ultimate victory over Lord Voldemort
Nowadays term 'alma mater' doesn't refer to a person, but a school, so it would be Hogwarts.
Ginny Weasley.
Mrs. Norris is Filch's loyal and overbearing cat in the Harry Potter series. She is often seen prowling the halls of Hogwarts alongside Filch, keeping a close eye on the students and reporting any rule-breaking to Filch.
Hopefully there will be when Pottermore is fully released, search it - pottermore.net!