You could just go find the other wall locations without the dead easy hint system. Losing the hints because you cannot get one location cleared is hardly something that should prevent you progressing. You can complete the game and never even bother with the hints.
As I have already said, I have found several since, though it is easier when they tell you where to go. I also don't like having a quests stuck in my journal forever either, but as you said I can still progress in the game.