Nice singing, Dave, but I'm hearing what you are saying... It all sounds a little clouded, there's no crispness to the vocal.

Mind you, the piano is kind of sitting front and center to it all, makes it hard to hear the detail in the harmonies, and forget about the drummer! He might as well be in the next room!

Here's something to test... Do the vocals and harmonies get sent through any final EQ and compressor in the arranger? Maybe you could dial those back (or off!)? It's possible that they are overhyping the arranger (piano sounds a bit crispy) and making it hard for the mike to compete..? You might also be hitting the compressor a bit hard, and clouding the sound with that.

Try it all effects off, see if that helps...

Overall, I thought the basic mike sound was just a hair too beefy in the low mids, and lacked highs. Maybe the Korg wants to see something a bit thinner and crisper in the way of a mike?

And give the drummer some! Hard to lock in on a tempo you can barely hear over the piano!