The headband looks a bit funky. Is this a reference to something?

that mustache does not look right

It's honestly a solid concept but it does need work! The beard and hair looks very flat and also has the edges which might seem a bit too sharp, with that, the small bit of hair above his head makes it looks a bit too odd, i think if you removed it or made a style to remove it, it will open it up to be much more usable. Good job otherwise!