Guys, Haru was introduced at the end of novel 2, and it was specifically mentioned that she reminded Sayaka of Yuu, so it make sense that there's a resemblence, It's not the author being sloppy or making all their characters look alike, it's an intentional coincidence.
And the dark skinned girl is only in the childhood part of the novels. most people don't end up with their childhood crush, contrary to the expectations engendered in us by romance manga.