I might do a devlog with some more hints, and if I do I will include this info.
That being said:
- Rashmi - Trigger traps (any kind) a total of 50 or more times.
- Jacqueline - After Rashmi is unlocked, there is a small chance that you will unlock her after a run (win or lose). That chance increases GREATLY after you beat the "Island - Large" mode.