My daughter is 5 and my son is 1.5. Im going to ask in school to see if they are going to have some type of celebration. It would be cool is the Plaza's had a little event for the kids. That would surely get them more people to come to the business and more sales too.
Halloween is an American holiday -- and most dominicans think it's 'bad' or at the very least weird. Unless your kids are in a bilingual school, I doubt you'll find anything. Adults like Halloween here because who doesn't like to dress up and have fun? (but not their kids, that's demonic)