Oh, and I think the issue might be related to the player's movement. The voodoo doll event is only triggered after checking the doodle, but it seems the direction the player is moving may be preventing the event from triggering properly.
As for the classroom investigation, only interactions that are important for story progression are counted toward the requirement to leave the classroom. Objects that only contain insignificant dialogue are already excluded from those requirements.
And I'll be addressing this issue in an update very soon :>