1. Good question that actually makes us realize there's a detail left out on the bit about communication devices... so with the medallions, what name they'll "respond" to is the name your character gives the coterie. Obviously this has the potential to lead to a lot of Shenanigans if your character is the type to give out fake names and things like that. The same will actually work for the journals, if your character chooses to get one: in order to "activate" it, they'll need to sign their name inside the cover, and from then on that will be their signature whenever they create any entries (including voice to text; the signature in the book will override whatever name their medallion thinks it's supposed to be, if that makes sense). Definitely going to clarify that on the FAQ page proper and add a bit more detail to it but that's the gist!

2. Similar to how the incense will muddle normal senses and perception, magical ones can be either weakened, over-heightened, deadened entirely, etc. depending on how you'd like for it to affect them. Characters with preternatural hearing or reflexes will have them become progressively less sharp, or maybe too sharp, and so on. Basically anything that can go wrong will go wrong, if you want it to.