User blog comment:Pochichi/Aikatsu Stars Presentation/@comment-26727523-20170306234842

There is a chance that Koharu will change to being a Cute Idol, but maybe they finally pass that rule aside and there are 2 Sexy types this season...It's like Mikuru!

So, Eimi's voice fits Koharu wonderfully, but it's not very likely, and if it were not the case, Ruka's voice would be fine.