I don't see how just having a love triangle makes this a harem >.>
Spoiler (highlight to view)
And even that love triangle is just barely there. Kurosawa doesn't even get the same exposure normal harem characters do ala Ouran, Ichigo 100%, Umi no Misaki, Love Hina, Negima, etc. He's just there, shows up from time to time then disappears.
Considering Fumino is already very much in love with Ojiro and is his wife I doubt this will become a harem.
Basically..(total spoilers btw)
Spoiler (highlight to view)
Shouma just wants his bros attention but he acts like a brat to get it. Him going after Fumino was because he knew it bothered him and he wanted attention from his bro. He went about it the wrong way and Fumino helps push Ojiro to correct it. They seem to be on better terms later. Kuro doesnt show up often enough and seems like more of a background/plot device character. He just shows up to make Ojiro jealous and act suspicious of their relationship. Fumino rejected him already. With one word no less. :haha: