Hakuba is bisexual but he already have a girlfriend and all the days covered. Elphaba...is supposed to be with Jack frost but know he told her to start dating other people because Jack refuse the idea of being 'owned' as Eris said. Elphaba is fine with it, she's not jealous. And I think that she don't really care for the gender.

Tatsumi is in love with Kasumi, yes. So no bad touch with him because he didn't confessed yet, but he's and old fashioned guy and really loyal :D