um..just so you all know, May and Dawn were named after their video game counterparts, not the otherway around. Otherwise Gold/Hibiki will have to be Jimmy, as his counterpart is called in the anime.
Also, I noticed that the player characters have different official names in the games, for instance, Gold's official names as of now are Gold (the original name), Soul (what he was called in HG/SS trailers), & Hibiki (Japanese Pseudo-Rival HG/SS name). Kotone's names are also different Heart (what she was called in trailers as the player), & Kotone (what she's called as the Pseudo-Rival in the Japanese HG/SS).
However, as was previously stated, I think Melody is a perfect English name for Kotone. Its close to Kotone's meaning (Sound of a Harp) and it'll even work for the anime Kotone since it has the same syllables (Ko-to-ne & Mel-o-dy), so they won't have to change it like they did with Lorelei by calling her Prima because of her Japanese name (Kanna) having only two syllables while Lorelei has 3. However, if Kotone's called Melody in the anime, she'll lose the pun made of her name in the Japanese version. In the Japanese anime Kotone says "koto ne" after some sentences. "Koto ne" is the Japanese equivalent of "Right" as used in "You think so too, right?"