No, per the instructions: "They have to appear, mentioned only does not count". None of the hogwarts founders are physically present in any scene at any point.
got 29/35, would have been 30 if I wasn't so lazy, I tried just "norris" for the cat and then gave up.
Out of the ones I didn't get, Katie Bell really surprised me. Can't remember seeing her on 6th and 7th books, I thought she was on Fred and George's year.
She is in the year after Harry, Ron and Hermione. In half-blood prince, she is the one who touches the cursed necklace. In deathly hallows she is involved in the so-called "Battle of Hogwarts"
Out of the ones I didn't get, Katie Bell really surprised me. Can't remember seeing her on 6th and 7th books, I thought she was on Fred and George's year.