Okay, so Hermes works stupidly well, imo. My thought is to give him a lyre, and the ability to - well, for one thing, to play it, but also to heal with it, since Hermes had medical connotations iirc. Also! Hermes' staff could put people to sleep. Maybe something with that, but through the lyre's music?

Also, definitely winged anklets! He and Della can be questionable fliers together!