The canon ending is the one where Mio strangles Mayu, lifting the curse from the village and having Mayu forgive her before turning into a crimson butterfly and flying away.
If the game is left idle for about five minutes, the face of a limbo woman ghost will appear sporadically on the screen, like a screen saver.
In Japan the game is called "Zero," or "Project Zero." The term "zero" is used in the game as the most powerful camera shot. The team who made this eventually became known as "Project Zero," even when they were not making Fatal Frame games.
Mio appears in Fatal Frame 3, continuing her story after the events of Fatal Frame 3 as a side character.
Mio and Mayu are not the first people who get stuck in the lost village, if you read all the documents you will find that hikers, forest workers, and just people taking a walk have all ended up taken by the lost village. Most of them became vengeful ghost still trying to escape the village.