6. Wasn't The Time War Time-locked?
It was, yes. But not even the Doctor knows how they got in; there was a comment "this should be time-locked". Maybe it was the paintings that helped, but then there was the portal that opened up for each Doctor. The War Doctor claimed it was the moment that showed him his future, so maybe that's where it came from? Again though, pretty difficult to write an episode about the Time War without unlocking it. Maybe it was always unlocked, but no one ever thought of checking: wouldn't be the first time, it would seem.