Flashback to 2011, when Fonchi & Yazawa still in group. During Mechaike Idol Battle, clearly that Idoling really have a lot of potential in terms of body height, they're above average for standard Japanese women. Just take a look form this picture from the show back then :
Can't you see how tall are them (Yazawa is exception
Sorry Hatix), Ton-chan maybe not above 160++ cm club, but as far as i know, she's almost 160 cm height (around 157-158 i think).