1) I have not looked for one, but I assume there would be a wiki?
2) Yeah, they're randomly generated, I've never encountered a repeat non-scripted character across any of my playthroughs.
3) Nova has scenes in the near-end of Tavi's storyline and an appearance in the fight club (if you would like instructions for accessing the fight club, I can provide).
4) If you mean the burly cat woman, Risha can be found in the gym, in Tavi's storyline, in Rahi's storyline, in Jackie's storyline, and in Artica's storyline.