So for ending two, you have to choose the reaver background, then have 80 points with Braums by chapter 5.
For ending 8, you need to be a Shika, and have 80 points with Rafael by the end of chapter 4. After this, his button should unlock on the start screen directly under the quit button. That will let you see the 'secret' route screen. There are six scenes, unlocked by getting different endings in the game. 15 is the max number of points you can get for him in the intro, so no worries there.
If you still can't unlock the endings but have fulfilled this criteria please let me know and I'll check the game for bugs!
And no worries at all, I'm happy to help!