Oh wow, I don't even want to contemplate all of those things :) I definitely think you are right though that this one little event could have such large consequences. Lockhart would have had no compunctions against using the memory charm on both boys, and had Tom Riddle been able to come to life from the diary by killing Ginny he would have been able to start his conquest of the Wizarding world that much sooner.

Laura//Hufflepuff