It took me all evening, but I managed one hell of a slog (for me, anyway) of a workaround and now can turn my RSS feed at Micro.blog into a WordPress import/export file which includes all my post categories, and even turns converts them instead into tags. Barring the unexpected, I’ve got just one issue left on the WordPress side, and it’s a true stumper: how to get posts without titles to generate post slugs, and therefore permalinks, using X number of words from the post rather than using a numerical slug from the post-ID.