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Some thoughts:
If anything you're thinking of is Latino-American, there are pages for that already: Latino-American Creators & Latino-American Media.
Look at Music Tropes and the "Genres + Subcategories" for how all sorts of other genres are set up. They aren't really pure indexes, but a description and history of the genre, plus associated tropes and prominent artists.
Any pages would need to be launched through Trope Launch Pad. Use an existing genre page's format as a template for Latin Music.

Should there be an index for Latin Music? The index would list all Latin music, but should it have one, or is it too broad, as it encapsulates a wide variety of genres?