this is a tough question! but if i had to assign them all... id have haruka, mikoto, and kazui be different shades of blue tbh. yuno would be pink? kotoko too, but a bit more on the hot pink/purple side maybe? fuuta is definitely red. muu would be yellow... amane would be a turquoise-teal color too i think itd fit her... shidou would be an ourple color, and mahiru DEFINITELY would be an orange