It's worth noting the "idol" costumes don't make them look like jpop idols so much as it makes them look like a marching band.Technically, yes. But most of them are fanservice. You have serveral bikinis, and a maid outfit for all the girls. And there are 'idol' costumes for all the girls and boys.
I really like Sonia's base outfit, but I totally agree with you about Yuma. Unfortunately he only has one alternate outfit, and it's the Idol uniform.
Also, each girl having 6 bikini costumes means I can cross off swimsuits on the bingo card.