Hi! I'm down to give you a hint for the 3rd ending if you'd like! Feel free to let me know if you're stuck, and I can give you the full answer in that case. <3
SPOILER:
1: During the date, try to be as rude as possible and hide as much information as you can.
2: Interact with everything in the cafe until Serze comes out of the bathroom, then speak to her.