So I had this thought. Miku is Sonic. Because blue. Shut up. And then Rin and Len are both Tails because yellow and there are two of them (like how Tails has two tails). Meanwhile Teto and Neru are Mighty and Ray (basically color swaps of Miku/Sonic). But in this analogy there isn't an official vocaloid with red hair who is popular enough to warrant the knuckles comparison