Should I do a new card reading at the start of every Curse of Strahd session?

Is it intended that an assassin must surprise their target and win initiative to use assasinate?

Is Wild shaped Druid considered a beast for the purposes of a dryad’s charm ability?

Is the extra 1d8 damage from the Ranger’s Colossus Slayer mandatory?

Does Open Hand monk’s ability knock the Tarrasque prone?