I'm glad to see you're enjoying the game! I appreciate you noticing the effort and pointing out the pros and cons. Thank you for the comment, as I'm always looking for ways to improve the overall experience.
To answer your question: I said three new characters instead of four because Iris, Liam, and Wyatt will be featured and explored in their routes, while Bork is a side character and won't have a route available.
Of course, you'll be able to explore Iris's route in the next update :D
I hope that clears up the confusion.
Again, thank you for playing, and I'm really glad to see you back!