All comments have imported successfully for librarian_films and relation_ships as of half an hour ago. I discovered and cleaned up one case of Russian spam in the form of a truly massive wall of text in a comment of the latter from about a year ago, which went unnoticed (but screened, even following the import) until now.
As planned, both communities were deleted from the Livejournal side once I made certain that everything was in order. Following input in favor of not going that route, I plan to leave big_damn_quests in both places. It's safely backed up here on Dreamwidth, should anything worse remove it over there.