I've been playing the game from some time, I really liked Kate and Damian, the best love interest in the game for me is Kate, her best route was the innocent one, the writing was very good, it would be nice to have a yandere route for Kate.
For Kate it didn't seem that she could have a slutty route, the differences between the innocent and slutty routes makes it a bit difficult to think that she have a slutty route and it's more difficult if you play the innocent route first, so I think that maybe there is a possibility for a yandere route.