Prompt 1 is indeed meant to be ambiguous. In fact, all of them can be taken one way or another. For example, does prompt 6 mean plans for an elaborate bondage session, complete with shibari, or that Severus *sighs* is crap at knitting? Or is prompt 8 a determination to lower his personal shields and admit his soft, squishy centre or is it your dub/non-con scenario? Even the very ambiguous prompt 1 could be a misunderstanding -- a lovers spat, the world shifting after a fabulous orgasm, or a death!fic?
Therefore, and with options like these, I'm afraid you are not permitted to take the fest title as a theme. After all, where would be the challenge in that?