As for Gold vs Golden: I'm a little messed up, and it doesn't help that the Metal Color chart is written in crazy english.
Gold attributes are closest to what I have in mind: excellent defense, gear-centric, fitting on a boy who has nothing but desires all the world. The chart also says left has high special attack? I think? Which again befits Memoriam Eternal.
Golden however comes from the card name which gives Golden Cub his leonine form, girth, and emphasis on hot-swapping Enhanced Gear stored within Memoriam Eternal.
So, I don't know which is appropriate.