@kuronotenshi
true, the mangaka didn't give her a chance to shine. But i think the next chapters maybe for Yotsuba, her arc won't be this fast, and besides the title won't be Go-toubun if she's out as candidate without a fight, unless we're near to ending.
Based on everything we've seen so far -- removing from the equation the girls' feelings for Uesegi... He seems to have had the most emotional interactions with Nino. So I think the question should be, rather than which girl loves him is which girl, based on what we've seen, would he love?
He can never give up his job as tutor, much less to some shady jerk. And not just because of his or the sisters' feelings, but because it's a financial necessity (even if the original deal has been altered/denied, his decision to help the sisters was heavily determined by his financial position). :)
Rena Yotsuba repeating the same "there's no way that would happen" of fuuts in his own casual speech at the end broke my heart so haaaaaaaaaaaaard, bye.. emo for a month
At least miku was zoned too lul.