Yael’s route is unlocked at the start of the game and contains a total of 2 Ends (1 Good & 1 Bad).
Yael’s route has a lot of overlap with Takeru’s route, though I recommend playing Taker’s route first.
Completing all of the endings in the game unlocks a special Epilogue.
After completing the epilogue once, Staff Comments and Standing Portraits unlock.
There is no strict “recommended” play order; except Towa’s route is locked until you complete either Takeru, Yael, or Ango’s routes. Complete those three in any order you please, but for the best story progression my personal recommendation is as follows:
Takeru > Yael > Ango > Towa > Epilogue
Lkyt contains heavy themes that may be uncomfortable for some players, I have noted all relevant content warnings at the start of each path.