I'm not familiar with most of these questions, but I'll take a stab at it!
1) I wasn't aware djed had a visible color. Could you be referring to res, the stuff reimancy uses? (Reimancers turn their djed into res before making it an element, as I understand it). If it's res, I believe the color depends on the person.
2) Developing an NPC for a location is something that goes through your local storyteller. Just PM them the idea for your NPC, and they'll either say yes or know or let you know what you should change. If your NPC works, they'll add it to the location
3) I am not at all familiar with the university, but my understanding was that classes were essentially as time-consuming as a job, and there are very few circumstances that allow for two jobs at once. But I would ask your local storyteller (I believe that would be Eldritch for Zeltiva), and see what you can work out