Incidentally, unless there are any objections, for that first story arc I'd be interested in adopting the basic set-up which I developed after coming up with that earlier "dungeon crawl" example: the PCs are enjoying the hospitality of the royal court during a visit to Aelfscienne, when things begin to go terribly wrong somewhere far below... I'd still like to tailor the details to fit the actual characters, of course, but that should give you at least some indication of what might lie in the future.

Still, if all or most of the Familia are recently enNobled and if you want a softer landing into the setting, it wouldn't be a bad idea at all to start out with a short introductory scenario, set in the hundredth night if the Chancel is new as well, and play through their first encounters with the Imperator.