Cap the depth of forking to 3.
Automatically generate post reply titles.
Implement permissions for students to see forums. Tested that they can edit their own posts but not others, delete their own posts, cannot reply to locked topics, cannot view hidden topics.
Allow students to delete their own posts and topics, and allow replies only to unlocked topics. Also make sure when someone sets the topic type that they are allowed to set it.
Students can set the answers of their own questions.