thanks for getting back to me. Too bad you're too far away for a spontaneous coffee together :).
Yes, category archives. It's a list of posts from the category, with more or less info depending on the theme, of course. However, I had this already enabled, but even though I have a post with that search term in a category, it doesn’t output the category page as a result. Is that supposed to happen?
Category custom fields. Well, yes, that is new, but with Advanced Custom Fields you could store them already since quite a while. This way I am able to give a WYSIWYG field that contains more options for the site's backend users. If you find time to evaluate it, that would be great. My customers misuse the field to store a lot of information and would like to have it included in your plugin's search results ;).
All the best