5 DIY Harry Potter Party Ideas - Party favors, decorations and more! Michelle's Party Plan-It
The one about Professor McGonagall not being the headmaster isn't true if you read Harry Potter and the Cursed Child
Rowling actually wrote and published a version of "Fantastic Beasts" for us muggles to read. The book is an encyclopedia of creatures, with a foreword from Dumbledore himself. The niffler and bowtruckle are definitely in it.