@shad haha right as I was reading your post I got one. Apparently, you can't redye the leprechaun hats. You can redye the sash but not the hat.
Well, bad news is that I can't use that hat for what I originally intended it to be used for. Good news is that I now have an article of clothing to base a character's outfit around. I've started doing that, lately. I recently acquired a xmas 2016 bone mask, and based a whole outfit around that. I have a few characters that need a new wardrobe, so I'll probably build one of them around the lep hat.