I think Nightshade might be overpowered then. If it controls darkness, then it can literally kill you from inside your body, cause light almost never reaches the inside of your body. If Nightshade's only ability is teleporting from shadow to shadow, it can be pretty interesting. I'd hesitate to accept someone who like, creates tendrils of darkness out of shadows. 

The others seems fine to me now. With the exception of Tempus. I wouldn't trust anyone, not even myself, with controlling a time-traveler xD If it's just seconds, though... It would be kinda UP, wouldn't it? Most situations you'd find an use for that ability would be situations where you'd already be dead when you realized you needed to go back in time. Like disarming a bomb or moving to a different piece of cover in a shooting.