The killing curse will cause anyone to be struck by it to die immediately. If the player uses the killing curse on Harlow, instead of it killing him, he's still alive and after defeating him, it's mentioned that he'll be sent to Azkaban for the rest of his life.
Inferi are known to stay in very dark places because they are repelled by anything bright like the sun. Many times during game play, Inferi will come out of the ground in daylight and attack the player and even appear in brightly lit catacombs.
To safely approach a Hippogriff, a person must first bow and wait for the Hippogriff to bow back. If the Hippogriff bows back, then it's safe to approach. When the player and Natty go to rescue Highwing and another Hippogriff from the poachers, Natty doesn't bow to the Hippogriff in front of her, she just gets on it. Since she never bowed first, she would never have been allowed to go near it.
In the Caretaker's Lunar Lament quest, Mr Moon refers to his childhood country with the modern name of "Korea". In 1890 when Hogwarts Legacy is set, Koreans referred to themselves as Joseon, the name of the dynasty that ruled the country from 1392 to 1897.