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