Hey, looks good! Haha, all I've got to worry about this year is a bit of black around the eyes for my mask. I don't even want to do that, nonetheless layer it on my whole face. Good luck to you with the rest of that.
The only thing I'd mention is maybe a whiter white? Err, more white anyways. It might just be the picture or I could be seeing things wrong, but with exception to the battle scenes the joker lays that stuff on pretty thick. And I'm sure you've got dozens of reference pictures, and this one is pretty common, but I wanted to mention is for the eyes:
Kind of like a side-ways 0. You'll have to improv most of that, because like dogman mentioned, all Heath's makeup was tailored to his face. You guys have very different features so don't be afraid to change what ever you have to. The eyes use a lot of natural shadows:
Thats a good example. Compare it with the first one and while the makeup doesn't follow that exact shape, it does use it as a major guide.
Anyways, hope you have a good time and everything goes well!