As for Darth Tormen, I doubt it. Seeing as we had the option to kill him, and it has not be confirmed that is canonically alive, it is unlikely he will appear. If he were to become a Dark Council member, it would have to be outside of the game. For if the BH encountered him again, he'd be like 'hey I killed you!'.
So it could be non canon, just like many choices in KOTOR 1&2 and Force Unleashed. Overall the DS choice makes more sense.
As for Darth Viktus, again unlikely. While I can't be sure he doesn't seem to much of an important character, just a sith lord you meet on Alderaan - he also doesn't seem to have anything to do with Biotic Science, more like Expansion and Diplomacy. Most likely we'll be seeing a brand new Sith, like Rictus or Aruk.
Alderaan is a very important planet even in that era, so the one who's handling it should be some important figure.
Too bad Severin got wasted, I really like him.