Here is the full list of all 9 Together - there are A Wish No One Remembers achievements.
Reach Allison's ending
Reach Sarah's ending
Reach Lara's ending
Reach Lara's side ending (A)
Reach Lara's side ending (B)
Reach Allison's side ending
Reach Sarah's side ending
Reach the end of the game
Reach the true ending