I’ve been leaving comments on anime channels about how this is marked as “yuri subtext” and so far, the replies and reaction has been very positive. I hope to see more of Shy in here as well.
A lot of the time when artists contrast two characters' colour palettes, it's all in their clothes and you're supposed to just kinda ignore the skin color.
But thanks to her hair, skin colour gets associated with Lumine while the blue in both of their outfits gets associated with Furina, balancing the pic in a really nice way.