I have some additional thoughts to add quick. Expanding beyond the monks, could there be a possibility that somehow students or other residents were the ones involved in his disappearance? There is the Collegeville institute about a 5 min walk from Metten court where he left the card party from. I attended a party before covid down fruit farm road, about an 8ish min walk from Metten, in a house that housed students but doesn't appear on the campus map. That whole area is populated with students and parties on the weekend. Not to mention that down that road there is the locally used Parish center and Prayer house. Though I doubt anyone would be using either of those in the middle of the night stranger things have happened.