So Babara (Yangs voice actor) says Yang is in love with Blake and that many things already planing at the beginning of Vol.1, and that we just watch what happen in the future.
I'm the only one, who think they really love each ohter even in the show? Ayano and Chinatsu are like crushes, but Yui and Kyouko have a deep bond and many moments without jokes togehter.