In the files section you can add categories for the files under the tab "Manage categories"

1) However I see no option to edit category file names. This would be a neccesity for correcting mistakes in the category names

2) Would like to see a sort field/setting for the categories so you can set the order of the category names. Now I have to use a workaround like:

a - my first category
b - a very first category
c - oops, a mistake

3) Is there a way to delete categories when there are nog fiels in the category?
Probably this sorting can be helpfull in other areas of activeCollab as well