Q: Is Ruggie actually the vice of Savanaclaw?

Ruggie is not a vice-housewarden, but there was a translation error on EN that might have caused some confusion:

Leona explains: “Some dorms send their vice housewardens (to meetings) instead, but our dorm doesn’t have one. I figured anyone in a support role would just create more work for me, so I never appointed one.”

But he may have had a few hopefuls in the past: in a voice line Leona says, “Where’s my vice housewarden? A few guys took up the job, but they all challenged me, lost and quit. I don’t have one right now.” Jack and Jamil also comment on how Savanaclaw has no vice-housewarden.

The mistranslation was Azul saying, “(Jack) is an underclassman in your dorm!,” when trying to get Ruggie to control Jack. This was written as “You’re his vice housewarden!” for the first release of Beanfest, corrected to “Your dorm. Your responsibility!” in the re-release.

So yes! Savanaclaw has no vice housewarden (just like Ignihyde) and it does not seem to be a secret at the school (also like Ignihyde).