Board Thread:Questions and Answers/@comment-66.250.190.31-20130716162252/@comment-50.175.29.173-20140712004641

At this point, it seems like, if anything were to become canon, it would be one of the Mikoshiba brothers, since Seijuurou has been hinted at since season 1 but now that he's leaving Samezuka, there's Momotarou to take his place. So really, from an unbiased point of view, they would be the ones that KyoAni would be shooting for. As for Haru, like the above said, there are a lot of BL hints, especially between the two largest ships of MakoHaru and RinHaru, but I doubt the producers would create anything canon out of it because the fanbase is large enough that there are going to be quite a few people offended by it, and they can't risk that.

Overall, though, I agree with the above commenter, because Free! isn't a romance, and as such, pairings aren't necessarily a requirement for KyoAni to explicitly say who is going out with whom.