Checked myself: No, the romantic dinner in the tavern can happen before killing Selye. My Mistake. Thane Hell Kitchen Quest also got no influence so i edit it out. I triggerd the Event by visit the Bull's Grave (Axel + Thane convesation) and talk to Nauxus so he shows you his drawing and his origin story. After that the romantic dinner should trigger the next time you return to the tavern (evening).
To invite Nauxus into the bathtub, you need to finish the Snow Mountain Questline first and return to the forest.