Maybe? It was whichever run JA increases damage taken by a specific element, I could only get damage increases for light damage(edit: including when her hands were dark). A real run player I knew tested this as well at got the same result. IIRC she did crap damage to light elementals in sky as well, but those might just have light DT not resist? In all of these cases it was right when arciela 1 came out thou, so something might have changed.
Gambit increases dmg to an element. Rayke lowers resistances and can lower elemental sdts if they have them and does some weird stuff to the nuking too much too fast dmg nerf. Hand color changes were mode changes iirc similar to light/dark arts where would go more towards support or enfeebling.
Elementals have huge sdts as well as immunities to debuffs to elements they are strong too which sort of makes it hard to tell if they have resistances too but probably. Light elmentals also tend to keep shell on themselves too.