I'm pretty sure that treating Eunice that badly will come back and bite him right where it hurts. I mean, she is a kid and you simply can't lower yourself to that level.
BTW I don't buy that "two-faced bitch" Stephanie's act.
Love the fact that you kept them: like you said; the uniqueness of the character is lost. Like not having a Tsundere say "baka". Besides if you are a manga/anime "lover" you should know this "things" already.
Edit: Thanks for the chapter!!!
And then Tsubasa got married with his neighbor senpai who picked him up after having his heart broken by the "I'm goin' to Korea without telling you how I feel nor asking how you feel, Gyaru", the end.