Gorgeous colors.
Okay I get what your saying. However I feel a character being self conscience about their body around their "love interest", or the "yuri-genre blushing" as you put it, is a good way to distinguish between romantic love between girls, and friendship, or simple administration.
Honestly I like my yuri pretty straight forward, as you probably have guessed by now. I don't mind a long journey up that yuri hill, but I just want some assurances that I'm not going to be disappointed with just an ambiguously close friendship, as a reward.
Wait, did you not see Fuuko blushing and trying to avoid looking too much at Himawari-san for almost the entire time they were in the bath?