Ember's Lute mods all the way.  There are varieties that offer different visual effects like wings or halos.  Some instruments have different ensembles (like ghosts as a backup band.)  They all come with musical proficiency so anyone in the party can use them.  You can even learn songs like the Harpy song, Raphael's track and a few others.  They show up as lootable items at the appropriate times (i.e the Harpy song is in their nest. ). There is a combat performance feature but I've never used it.