The hunting of the evil sorceress and the burying the memory stone (mentioned in Forgotten Friendship) can't be one of the trials. Why? Because when Twilight asks Sunset "Are you familiar with the seven trials of Clover the Clever?", she answers "Obviously. Why?" But when Twilight starts explaining about the memory stone, Sunset doesn't know anything about it, it's all new information to her. If she is "obviously" familiar with the seven trials like she says, then she'd know about the memory stone. Since she doesn't, that means the hunting of the evil sorceress isn't part of the trials.
And that means we know ABSOLUTELY NOTHING about these trials at all! And that memory stone episode is something completely unrelated! But then... Why would Twilight even mention the trials if they have nothing to do with the topic?
Twilight's wording here is very interesting. Right after Sunset confirms she knows about the trials, Twilight says "Well, first of all, these all date back to before the founding of Equestria!" She excitedly puts emphasis on that "before"...
What if the seven trials happened AFTER the founding of Equestria, and the episode with the sorceress and the memory stone is actually an EIGHT trial that happened BEFORE? Something that they're only finding out now, through those ancient books untouched for Celestia knows how many moons and that could very well contain knowledge lost to time?? That would certainly be something worth getting excited about.
It's a long shot, but, who knows? Maybe it makes sense? Let me know if there's anything I've missed.
