Remit: What's even worse, the dead ghost woman in the mortuary didn't appear. 
  She only appears if certain conditions are met. I didn't have any invisible characters in my game.   
Remit: The problem can be fixed by loading the game or by exiting and re-entering the area. 
  The problem with TNO not initiating dialogue. Yes, that happend to me a couple of times, save/reload, no big deal since it's pretty obvious that something should happen. 
 Actually, I might have had a related bug. A portal towards the end of the game didn't appear. The portal was there, Nordom kept yelling about it, but it just wouldn't show. That was pretty frustrating, nothing worked until I kicked everyone out of my party and had them rejoin. 
 Anyway, expect bugs, it's an old game designed for a different OS, but ask here and more often than not you'll probably get a solution.