Random speculation:
Someone on H!O theorized that the colors the girls were given when they spoke on todays Haropro Time were the colors of the girls. The Biggest Argument for this is that whenever a girl was introduced on the show they would use her official color, so it stands to reason we have 10th gens official color. I don't know, it seems logical and crazy all at the same time. Since All we have at this point is random speculation, lets go with it.
Haruka:Orange.
We're off to a good start here, Haruka's birthday shirt was orange. This puts some Merit to the theory.
Haruna:Dark Red.
Okay... maybe Haruna's Bday Tshirt is Maroon and only LOOKS brown to us commoners. Someone who's gullible (Me) is going to have to wait till it comes in the mail (Me) in order to see. Maybe. (Sure looks brown...)
Now before you say "THAT'S JUST RED, WHAT IS THIS DARK RED BULLSHIT", Here's the color they used when they introduced Riho:
Ayumi:Dark Blue.
Using Junjun's old color seems realistic since there would be president because of Haruka's orange. That's the only justification I have for this one. It's a color not used anymore and it skipped a generation. I'm not sure what else would leave someone to think this is her color.
Masaki:Some kind of fucking green.
Here's where it kind of falls apart. They introduce Masaki with green. Would they really use a THIRD green? What color green could they possible use? Medium Green? What color IS Medium Green anyway? I don't know, let's say for Argument sake she is Green. She would be.... I don't know, regular ol fucking green. Not lime green like Risa or Dark Green like Zukki... just green. I'm sure this is possible, but it seems so redundant.
BUT just because I'm so god damn thorough you're eyes WILL BLEED, I screen capped Zukki and Risa.
Zukki's Dark Green:
Risa's Lime Green:
I AM BORED OKAY?
EDit: Looking at Masaki's green, it does appear to be a different color green but I'm raging against the Green here and don't want to add merits to the theory