I don't think the 3rd metaphor fits. rgb values still points to a single color, which maps back to a single value on a 0 -> 1 or red -> violet continuum. It's more apt to describe it like a multi channel audio mixer. Many different channels ("really into a specific topic", "freaks out at parties"), each with their own value (10%, 20%).

Metaphors often fail though, so it might just be best to say what we mean plainly.