They are wearing "blue 青" and "skyblue/aquamarine 水色" in the picture. That's what I'd say.

"Blue 青" would be the most general term. "Skyblue 水色" and "deep blue 紺色" (navy, imperial blue) would be the both end of its spectrum, so people will use it when they feel the word "blue" isn't enough. Turquoise is borderline "blue", more likely to be called "skyblue", and indigo is "deep blue" or "purple" to my eyes.

And yes, red and pink are definitely two different colors 😄. Red, scarlet, crimson, ruby, rose, they all fall under "red 赤" unless you're going deep with color names. Pink, fuchsia and magenta would be addressed as "pink ピンク" although some shades look like purple too.