I'm not sure if I see it wrong or not, but somehow Sayu and Koharu had this same white hot-pants (the one that Koharu wears in this photo), I mean sometimes you see Sayu wearing this white hot-pants I talked about, other times you see Koharu wearing it.
It's probably from wardrobe. Risa wore clothes one of the other girls wore too.
Having other members wear similar or the same clothing isn't something new, they even 'recycle' bikinis.In the second Morning Musume "Alo-Hello" photobook, Eri was wearing Nacchi's hot pink swimsuit from the first one. And Sayu was wearing Kago's red one.
I don't think it's UFA that are recycling the bikini's but it's the photographers or the company that they work for as I'm sure they have their own wardrobe for the idols. I've seen a lot of similar bikini's that have been worn by not only among H!P girls, but gravure idols as well, for example I've seen this picture of Takahasi and Aki Hoshino(if I'm not mistaken) wearing the exact same bikini/swimsuit.
I was really looking forward to a Sayu PB when Reina and Eri both got their PBs early this year..Maybe UFA's planning something special for her when she's about Eri's age when 17sai came out. I hope it's gonna be as classy as Maki's Foxy Fungo, that PB is simply incredible!EDIT: Incredible as in "Wow! Great shot! This photographer is great!" kind of sense. Not the "HOLY F*CK I'm bleeding through my nose!" incredible