There are a couple of plugins that allow defining structured data in DW pages
1)
http://wiki.splitbrain.org/plugin:template
2)
http://wiki.splitbrain.org/plugin:templater
And this discussion is very interesting to creating pages with a list of templates:
3)
http://wiki.splitbrain.org/wiki:discussion:wikitemplates
I'm not sure if that is what you want.
Categorizing a page is setting the subject of the page to given key words. It can be done with the tag plugin
4)
http://wiki.splitbrain.org/plugin:tag
This plugin also has the function of listing all pages with a given tag.