Good choices to start with. They are both very close in overall capability with only some bit of an edge going to one or another depending on your requirements/expectations.
One notable difference here, if you're going with the PE boxes is that the one for the 18" will obviously be a bit larger. That enough could be the deciding factor for you or someone else. I have no idea. We need more details from you.
Skip the inuke1k. Don't use it for subwoofer duty. Go straight to the 3k or 6k.