@PankoSure. My thought was that they've probably done some projects together, as some projects would've been Guardian-exclusive, and the Guardian population in each division isn't awfully large. And we can totally just leave it at that! They do seem to share an interest for the actual navigation part of the Navigation Division, from what I understood.
Most of the rooms at the dormitories would be single rooms. I imagine that there would be a few rooms designed for two people, but it would be for students that came as a couple, usually siblings. As for different programs and projects—yes, there can be some of these. You'd have to make them yourself, though, as thinking of all the possible combinations myself would be a daunting task. However, the academy would indeed encourage cross-division interaction outside of regular schooling.
Spirits are not corporeal. In past iterations of this roleplay, I've had creatures similar to summons that are massive congregations of spirits that do become physical entities, but I left that out this time around. Guardians, in a sense, is the physical manifestation of spirits, i.e., their corporeal form.
@WhoamiHey, hey! ♥
Looking forward to it! We need more lovely ladies in this.