You have just changed your question.
It is possible for a company to have a listing in a Regional category, if the company has a regional interest, and then additionally in a so-called "Topical" (i.e. non-Regional) and then, for every language that the site is written in which is not English, an entry in a category in the "World" tree. Each of these should be for the same URL, though.
For every guideline in the ODP there are exceptions, some more exceptional than others. Looking for hard-and-fast regulations would be a futile activity, in my opinion.