Interesting summary of the roots of Halloween. It is, however, not as widespread as you describe it. Here in Germany for example, it was basically unknown until the americanisation of the culture. Even today it is not a real part of german customs. Some people do it, I guess, just because its fun to dress up and get some free sweets.
We do have customs, though, that remind of Halloween and go back way before the christian time. Especially in the south of Germany, in spring groups of people dress up as demon like figures and make processions through their villages, trying to spook the spectators. They make a lot of noise and weird sounds, dance around and so on. Its said that is meant to drive out the evil spirits of the winter. And it has nothing to do with sweets... :)