Yes, but Water has access to an additional -10% ATK from Jorm as friend eidolon. Also, Frost Raphael synergizes well with Cthulhu, as I explained in my guide for Water.
Sol is a fine choice too, but somewhat redundant if you already have Gaia and SSR Nike. And fielding both Gaia and Sol at once would lower damage substantially, which probably isn't desirable.